Combo with Organic Chemistry Reactions and 23 others
Electrophile
"Electron-loving" [Lewis Acids] Positively polarized species in a reaction Accepts a pair of electrons from a nucleophile
Nucleophile
"Nucleus-loving" [Lewis Bases] An electron rich or neutral species in a reaction C=C act as nucleophiles
explain the crazy ass Hydroboration transition state
"four-centered": four atoms are involved; in one giant ass step the pi bond and H-BH2 bond are broken and two new sigma bonds are formed (syn addition)
styrene
(C6H5)CH=CH2
friedel crafts
(benzene ring with R group) make R group add to benzene ring with AlCl3 catalyst
Montreal Protocol
- (1987) - agreement to phase out CFCs - atmosphere will recover by 2070 - nobel prize
Electrophillic addition to conjugated dienes
- 78°C --> 1,2 addition predominates (essentialy irreversible, no eq, faster rate) - 40-60°C --> 1,4 addition predominates (more stable) - gradual warming or acid catalyst creates a higher temp - if pure 1,2 or 1,4 addition is added with Lewis acid catalyst, equilibrium is formed
3 ways of naming alcohols
- Add the suffix -ol to the stem of the parent hydrocarbon; if the location must be specified, the number of the carbon atom to which it is attached is given. - Name the parent hydrocarbon as a group and attach the name alcohol, ex. ethyl alcohol. - Name the -OH group as a substituent, in which case the name hydroxy is used, ex. 2-hydroxybutane.
explain Hydro-halogenation stereochemistry
- Addition of Hydrogen occurs from both above and below, which can generate enantiomers (if a stereogenic center is formed). then the Nucliophilic attack by X⁻ occurs from both sides of the Carbocation, which can again produce 2 stereoisomers for each enantiomer (for a total of 4 stereoisomers; 2ⁿ where n = # stereoisomers). In other words: both syn and anti addition occur.
Synthesis: How do you prepare an ether?
- Addition of an alcohol, ROH (RO is the good leaving group). Mechanism: same as hydration.
Ozonolysis
- Cleavage of alkene or alkyne by reaction with ozone (O₃) - syn addition, but none at the end - Markovnikov's rule irrelevant - no electrophile
In which mechanism/s is a bridged halonium ion formed instead of a carbo-cation?
- Halogenation - Halohydrin formation
check this one out..Which mechanisms have 3 steps?
- Hydration - Halohydrin formation, water acts twice.
In which mechanisms does BOTH syn and anti addition occur?
- Hydro-halogenation - Hydration
Addition of Br₂ and Cl₂
- Markovnikov's rule irrelevant (no H) - anti addition - exhibits backside attack - as Br₂ approaches molecule it becomes polarized
Which mechanisms have 2 steps?
- SN1 - E1 - Hydrohalogenation - Halogenation - Hydroboration-oxiation -if considering BOTH mechanisms)
In which mechanism/s are carbocation intermediates formed?
- SN1 - E1 - Hydrohalogenation - Hydration
Which mechanisms have 1 step?
- SN2 - E2 - the Hydroboration part (oxidation is a separate mechanism) - Oxidation (hydroboration is a separate mechanism)
Arenium Ion
- a carbocation formed by an electrophilic attack on an aromatic ring - a reactive intermediate in EAS - be deprotonated, form pi bond fate restores aromaticity/is favored
Oxonium ion
- a cation with an oxygen with three bonds and a positive formal charge
Diazonium cation
- a cation with the general structure R-N⁺≡N
Azo Dye
- a dye molecule which includes the diazo functional group between two aromatic rings - most dyes are red, orange, or yellow
Sulfonic Acid
- a functional group characterized by a sulfur doubly bonded to two oxygens, a hydroxyl group, and a carbon of any hybridization
Chlorofluorocarbons (CFCs)
- a molecule containing only Cl, F, and C - used as refrigerants, spray can propellants, etc. - long atmospheric half-life
Elimination Reaction
- a molecule loses atoms or groups from adjacent atoms - results in a pi bond - useful for synthesis of alkenes & alkynes
Antioxidant
- a molecule that consumes reactive oxygen species, thereby preventing oxidative damage - biological defenses against radicals
Enol
- a molecule that has a hydroxyl group attached directly to an alkene
Add to a Pi Bond
- a radical fate
Atom Transfer
- a radical fate
Radical Combination
- a radical fate
Addition Reaction
- a reaction in which groups are added to opposite ends of a pi bond - the process is generally exothermic, as most pi bonds are weaker than sigma bonds - rate is bimolecular
Photolysis
- a reaction in which the absorption of light results in the breaking of bonds
Substitution Reaction
- a reaction where part of a molecule is replaced
Chain Reaction
- a reaction whose mechanism includes one or more steps that are repeated indefinitely until the chain is terminated - the term is usually reserved for free radical reactions Mechanism: 1. initiation 2. propagation 3. termination
Acylium Ion
- a resonance stabilized cation - most often encountered as a reactive intermediate of the friedel-crafts acylation reaction
Carbocations
- a sp2 carbon with 3 trigonal planar attachments and a formal positive charge - pz orbital is empty - common intermediates in organic mechanisms - wants electrons - desperate and not fussy stabilizing features: 1. resonance 2. degree of substitution carbocation fates: 1. capture nucleophile 2. deprotonation (base) 3. rearrangement
Free Radical
- a species with an unpaired electron - once formed, radicals react quickly - free radicals are electrophiles because they have open valence shells Fates: 1. add to a pi bond 2. atom transfer 3. radical combination
Intermediate
- a structure which is not a starting material, a product, or a transition state
Solvent
- a substance in which other substances are dissolved so they can mingle & achieve transition state orientation
Electrophilic Aromatic Substitution (EAS)
- a substitution reaction in which an atom or group attached to an aromatic ring is replaced by some other atom or group - H is the most commonly replaced attachment - attack of the aromatic ring by an electrophile Factors: 1. arenium ion stability (1°, 2°, 3°, resonance) 2. number of positions (2:2:1 = o:m:p) 3. steric effects Rate depends on: 1. nucleophilicity of benzene ring 2. arenium ion stability 3. strength of electrophile
Dielectric Constant (ε)
- ability of a solvent to insulate opposite charges from each other - ε > 20 = polar solvent - ε < 20 = nonpolar solvent
Catalyst
- accelerates a chemical reaction
Carbonyl Group
- acts as both an electrophile and nucleophile due to polarity - trigonal planar Three Fates: 1. accept nucleophile at C 2. accept electrophile at O 3. form enolate Reaction Rate Factors 1. resonance stabilization 2. δ⁺ on carbonyl C 3. LG 4. steric hindrance Mechanisms: 1. nucleophilic carbonyl substitution 2. addition
Catalytic Hydrogenation
- addition of H₂ in the presence of a catalyst - syn addition - Markovnikov's rule irrelevant (H₂ symmetrical) - H₂ is not an electrophile - catalyst usually Pt, Pd, Ni - calalyst alters mechanism but not [K eq]
Carbocation Rearrangement
- adjacent σ bond switches without base - in equilibrium, proceeds in a way that will increase stability
Concerted Reaction
- all reaction steps are synchronous
Cycloaddition
- an addition reaction in which a ring is formed
Syn Addition
- an addition reaction in which bonds are formed on the same face of the reactant molecule
Anti Addition
- an addition reaction in which two substituents are added to opposite sides of a pi bond - decreases bond order - increases number of substituents
Deactivating Group
- an aromatic ring substituent that decreases nucleophilicity and arenium ion stability - decelerates reaction compared to benzene by decreasing nucleophilicity Examples 1. Halogens
Activating Group
- an aromatic ring substituent that enhances nucleophilicity and arenium ion stability - accelerates reaction compared to benzene by increasing nucleophilicity - any carbocation stabilizing group - better electron donors = more powerful activators Examples 1. alkyl groups (-CH₃, -CH₂CH₃, etc.) 2. pi bonds (aromatic rings) 3. lone pairs (-OH, -OR, - NH₂, -NHR, -NR₂)
Steric Effect
- any effect on molecule or reaction due to the size of atoms or groups
Tautomer
- any molecule in a set of constitutional isomers that are conceptually related by the shift of a hydrogen atom and one or more pi bonds
Azo Compound
- any molecule with the general formula R-N=N-R
Reduction
- any process in which there is a decrease in the number of covalent bonds between an atom and atoms that are more electronegative - generally seen as decreasing number of C-O bonds
Oxidation
- any process in which there is an increase in the number of covalent bonds between an atom and atoms that are more electronegative - generally seen as increasing number of C-O bonds
Regioselective Reaction
- any process that favors bond formation at a particular atom over other possible atoms
Antibonding (σ*) Orbital
- approached by nucleophile during backside attack
Leaving Group (LG)
- atom or group of atoms which break away from the molecule - accepts electrons from C-LG bond Factors: 1. resonance (increases electron accommodation) 2. atomic radius (larger radius increases electron accommodation) 3. electronegativity (high EN increases electron accommodation) 4. inductive effects 5. formal charge Excellent: 1. sulfonate ions 2. iodide ion Moderate: 1. bromide ion 2. chloride ion 3. water 4. alcohols Rare: 1. fluoride ion 2. amines 3. oxyanions 4. nitranions Never: 1. alkyl group
Cahn-Ingold-Prelog priorities
- based on atomic weight
Homolytic Bond Cleavage
- bond breaking in which the bonding electron pair is split evenly between the products - often produces radicals
Heterolytic Bond Cleavage
- bond breaking in which the bonding electron pair is split unevenly between the products - often produces at least one ion
Trans
- carbon groups on opposite alkene face - more stable than cis (steric strain)
Cis
- carbon groups on same alkene face - less stable than trans (steric strain)
Electron Withdrawing Group (EWG)
- destabilize an adjacent carbocation - reduce nucleophilicity of aromatic ring by removing electron density
Electrophile
- electron deficient
Halogenation
- electrophilic addition - halonium ion (Cl or Br w/ Lewis acid) - mechanism: (1) Cl₂ + FeCl₃ makes molecular complex (2) Cl+ reacts with aromatic π cloud to form resonance cation intermediate (3) that loses proton to give aryl chloride product
Nitration
- electrophillic addition (NO₂+ ion→ Nitric + sulphuric acid) - mechanism: (1) protonation of nitric acid by sulfuric acid (2) loss of water (3) resonance stabalized cation
E2 (Elimination Bimolecular)
- follows Zaitsev's rule - consider before SN2 (exception: alkyl halides) reaction checklist: ☐ base (usually strong; RO-, not ROH) ☐ leaving group (moderate or better) ☐ molecular geomentry (periplanar β-hydrogen)
Halogenation pt 2
- halogenation of aromatic ring w/ -OH, OR & -NH₂ does not require Lewis acid catalyst
Transition State
- highest energy structure for each mechanism step in the reaction - has partial bonds
E
- highest priority (Cahn-Ingold-Prelog) groups on opposite alkene face
Z
- highest priority (Cahn-Ingold-Prelog) groups on same alkene face
Chichibabin Reaction
- hydride ion is a leaving group
Protic Solvent
- hydrogen bond donor
β-Hydrogen
- hydrogen bonded to a β-carbon
Crutzen, Rowland, and Molina
- implicate CFCs in ozone depletion
Meta Director
- in EAS, a substituent that favors electrophilic attack meta to the substituent - most meta directors are deactivators - any carbocation destabilizing group Examples 1. -NO₂ 2. -NH₃⁺, - NH₂R⁺, -NHR₂⁺, -NR₃⁺ 3. ketone, aldehyde, ester, carboxylic acid, etc. 4. C≡N 5. CF₃ 6. SO₃H (sulfonic acid)
Ortho/Para Director
- in EAS, a substituent that favors electrophilic attack ortho or para to the substituent - most ortho/para directors are activators (except for halogens) - any carbocation stabilizing group Examples 1. alkyl groups (-CH₃, -CH₂CH₃, etc.) 2. pi bonds (aromatic rings) 3. lone pairs (-OH, -OR, - NH₂, -NHR, -NR₂, Halogens) resonance outweighs electron withdrawing
Markovnikov Addition
- in an addition reaction of generic electrophile HX to a pi bond, the H of HX gets bonded to the carbon atom that has the greatest number of H atoms in the starting alkene/alkyne
Anti-Markovnivov Addition
- in an addition reaction of generic electrophile HX to a pi bond, the H of HX gets bonded to the carbon atom that has the least number of H atoms in the starting alkene/alkyne
Conjugation
- increases alkene stability
Degree of Substitution
- increasing substitution increases stability
E1 (Elimination Unimolecular)
- k [R-LG] reaction checklist: ☐ leaving group (moderate or better) ☐ carbocation (2° or better) ☐ solvent (polar, protic preferred)
SN1 (Substitution Nucleophilic Unimolecular)
- k[R3C-LG] - substitution at sp3 carbon in which C-LG bond is broken to give a carbocation intermediate becore C-Nuc is formed - there is a mixture of inversion & retention reaction checklist: ☐ leaving group (moderate or better) ☐ carbocation intermediate (stability must be 1° w/ resonance or better) ☐ solvent (polar, protic preferred)
Terminal Alkene
- less stable than internal alkene
explain Alkenes physical properties. solubility, melting and boiling point.
- low melting andboiling point that increase with chain length. -insoluble in water. -soluble in organic solvents
Arrhenius equation
- lower transition state energy leads to faster reaction rate
Hofmann elimination
- major E2 product is less highly substituted alkene occurs when: 1. base = (CH3)3CO- 2. LG = NR3, SR2, or F-
Zaitsev's Rule
- major elimination product is the more stable alkene
Chain Initiation
- mechanism step in a chain reaction that has no radical reactants and gives radical products
Chain Propagation
- mechanism step in a chain reaction that has radical reactants and gives radical products
Chain Termination
- mechanism step in a chain reaction that has radical reactants but gives no radical products
Internal Alkene
- more stable than terminal alkene
Periplanar
- must have parallel p orbitals between H-C and C-LG
Aprotic Solvent
- not a hydrogen bond donor
Carboxylate
- not very reactive
Back Side Attack
- nucleophile approaches antibonding orbital - causes inversion of substituents
Accept Nucleophile at Carbon
- one of three carbonyl fates
Accept Electrophile at Oxygen
- one of three carbonyl fates - requires strong acid
Nucleophilic Carbonyl Substitution
- one of two fates of a tetrahedral adduct - shown in all but ketones and aldehydes - faster because it is within the molecule (as opposed to addition which requires other molecules)
Addition
- one of two fates of a tetrahedral adduct - shown in ketones and aldehydes (no LG)
Energy Profile
- plot of reaction coordinate versus energy
Tetrahedral Adduct
- produced by nucleophilic attack on carbonyl C - changes from sp² to sp³ hybridization Fates: 1. nucleophilic carbonyl substitution 2. addition
Enzyme
- protein or RNA that catalyzes biochemical reactions How? 1. stabilize transition state 2. destabilize reactants
Base
- proton acceptor
Acid
- proton donor
Solvolysis
- reaction in which solvent is a reactant, and becomes part of reaction product - frequent phenomenon in SN1 reactions
Nonconcerted Reaction
- reaction steps are asynchronous
Electron Donating Group (EDG)
- stabilize an adjacent carbocation - increase nucleophilicity of aromatic ring by releasing electron density into the ring
Reaction Mechanism
- step by step accounting of bond changes
Furchgott, Murad, and Ignarro
- studied nitric oxide - nobel prize in medicine (1998) - UCLA!
Inversion
- substituents flip the opposite way after the transition state - due to approach of nucleophile to C-LG σ* antibonding orbital
Retention
- substituents remain facing the direction they were after the transition state
SN2 (Bimolecular Nucleophilic Substitution)
- substitution at sp3 carbon - nucleophile-carbon bond formation simultaneous with LG-carbon bond scission - k[nucleophile][electrophile] - substitution at sp3 carbon in which C-Nuc and C-LG bonds change simultaneously - no carbocation is formed - always exhibits inversion Checklist: ☐ nucleophile (moderate or better) ☐ leaving group (moderate or better) ☐ steric hindrance (LG carbon cannot be 3°) ☐ solvent (moderately polar, aprotic preferred)
Nucleophile
- supply electron for bond with carbon Factors: 1. resonance (decreases nucleophilicity) 2. atomic radius (larger radius decreases nucleophilicity) 3. electronegativity (high EN reduces nucleophilicity) 4. inductive effects 5. formal charge (negative enhances nucleophilicity)
Pulmonary Surfactant
- surface active agent - collection of phospholipids - contains three fatty acid esters whose hydrocarbon tails can suffer oxidative cleavage upon reaction with ozone - assists migration of O₂ from air to bloodstream
Hydroboration-Oxidation Reaction
- syn addition - anti-markovnikov - BH₃ is electrophile
Azo Coupling
- the EAS reaction of a diazonium cation with another aromatic ring to form a diazo compound mechanism
Bond Dissociation Energy (BDE)
- the amount of energy needed to cause homolytic cleavage of a covalent bond - a measure of bond strength
Deprotonation
- the electron from a C-H bond is used and the H is taken by a base
Tautomerization
- the process of isomerization of one tautomer into another tautomer
Photochemistry
- the study of chemical processes induced by the absorption of light photons
Freon
- trade name for molecules formed of C, H, F, Cl, and Br
Inductive Effect
- transfer of charge through a chain of atoms in a molecule by electrostatic induction
Rate-Determining Step (Rate-Limiting Step)
- transition state with largest Ea - has greatest effect on reaction rate
Aldehyde
- undergoes addition mechanism (no LG) - faster than ketone (steric hindrance/inductive effects)
Ketone
- undergoes addition mechanism (no LG) - slower than aldehyde (steric hindrance/inductive effects)
Carboxylic acid
- undergoes nucleophilic carbonyl substitution mechanism
Thioester
- undergoes nucleophilic carbonyl substitution mechanism - faster than ester (better LG, less resonance stabilization) - slower than anhydride
Ester
- undergoes nucleophilic carbonyl substitution mechanism - faster than amide (resonance stabilization/inductive effects/better LG) - slower than thioester (worse LG, more resonance stabilization)
Acid Chloride
- undergoes nucleophilic carbonyl substitution mechanism - faster than anhydride
Anhydride
- undergoes nucleophilic carbonyl substitution mechanism - faster than thioester (inductive effects/LG with resonance) - slower than acid chloride
Amide
- undergoes nucleophilic carbonyl substitution mechanism - slower than ester (resonance stabilization/inductive effects/bad LG)
Antiperiplanar
- usually favored over periplanar
Nonpolar Solvents
- ε < 20 Examples: 1. dichloromethane 2. tetrahydrofuran (THF) 3. acetic acid 4. ether 5. hexane
Polar Solvents
- ε > 20 Examples: 1. water 2. methanol 3. ethanol 4. dimethylsulfoxide (DMSO) 5. N,N-dimethylformamide (DMF) 6. acetone
Radical Addition of HBr to an Alkene
-A radical addition mechanism is followed -Br bonds to the less substituted carbon atom to form the more substituted, more stable radical
What is the electrophile in hydroboration?
-BH2 gets added as the electrophile.
Sec-Butyl
-CH-CH₂-CH₃ ↓ CH₃
Functional Groups: Aldehyde
-CHO
Isopropyl
-CH⁻CH₃ ↓ CH₃
Butyl
-CH₂-CH₂-CH₂-CH₃
Propyl
-CH₂-CH₂-CH₃
Functional Groups: Ketone
-CO-
Functional Groups: Amide
-CO-N<
Carboxyl Group
-COOH
Functional Groups: Carboxylic Acid
-COOH
Functional Groups: Ester
-COOR
Preparing an Epoxide - Method 1/3 - By treatment of an alkene with peroxyacid (peracid)
-Cis/trans configuration kept
Hydration formation of an Ester
-In this case the reactant is changed to H-OR and the product is thus changed from OH to OR. -The mechanism has three steps. -Carbocations are formed as intermediates. -Carbocations rearrangements are possible. -Markovnikov's rule is followed. H bonds to the less substituted C to form the more stable carbocation. -Syn and anti addition occur.
Functional Groups: Amine
-N<
Amino Group
-NH₂
Functional Groups: Ether
-O-
Functional Groups: Alcohol, phenol
-OH
Hydroxyl group
-OH A polar group.
Examples of nucleophiles
-OH and H₂O; the oxygen, in both cases. ex. water in hydrolysis
Hydroboration-Oxidation
-One step mechanism. -No rearrangements can occur. -OH bonds to the less substituted C. -Syn addition of H2O results. -9-BBN can be used as a substitute for the BH3
Halohydrin
-The mechanism has three steps. -Bridged halonium ions are formed as intermediates. -No rearrangements occur. -X bonds to the less substituted C. -Anti addition occurs. -NBS in DMSO and H2O adds BR and OH in the same fashion.
Hydration formation of an Alcohol
-The mechanism has three steps. -Carbocations are formed as intermediates. -Carbocations rearrangements are possible. -Markovnikov's rule is followed. H bonds to the less substituted C to form the more stable carbocation. -Syn and anti addition occur.
Halogenation
-The mechanism has two steps. -Bridged halonium ions are formed as intermediates. -No rearrangements can occur, -Anti-addition occurs.
Hydrohalogenation
-The mechanism has two steps. -Carbocations are formed as intermediates. -Carbocation rearrangements are possible. -Markovnikov's rule is followed. H bonds to the less substituted C to form the more stable carbocation. -Syn and anti addition occur.
Halogenation of Alkanes
-The reaction follows a radical chain mechanism -The weaker the C-H bond, the more readily the hydrogen is replaced by X. -Chlorination is faster and less selective than bromination. -Radical substitution at a stereogenic center results in racemization
Functional Groups: Halides (= F, Cl, Br, or I)
-X
Naming linear alkenes
-ene suffix Prefixed by a number corresponding to the second carbon bonded in the chain, ex. CH₃CH=CHCH₃ : 2-butane CH₂=CH-CH=CH₂ : 1,3-butadiene
***uyama Coupling
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***uyama Reduction
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Atomic Radius
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Baeyer-Villiger Oxidation
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Baker-Venkataraman Rearrangement
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Balz-Schiemann Reaction
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Bamford-Stevens Reaction
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Barton Decarboxylation
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Barton-McCombie Reaction (Barton Desoxygenation)
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Baylis-Hillman Reaction
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Beckmann Rearrangement
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Benzilic Acid Rearrangement
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Benzoin Condensation
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Bergman Cyclization
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Bestmann-Ohira Reagent
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Biginelli Reaction
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Birch Reduction
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Bischler-Napieralski Reaction
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Blaise Reaction
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Blanc Reaction
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Bohlmann-Rahtz Pyridine Synthesis
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Boronic Acid Mannich Reaction
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Bouveault-Blanc Reduction
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Brook Rearrangement
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Brown Hydroboration
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Bucherer-Bergs Reaction
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Buchwald-Hartwig Cross Coupling Reaction
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CBS Reduction
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Cadiot-Chodkiewicz Coupling
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Cannizzaro Oxidation Reduction
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Capture a Nucleophile
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Chan-Lam Coupling
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Claisen Condensation
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Claisen Rearrangement
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Clemmensen Reduction
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Click Chemistry
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Collins Reagent
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Conia-Ene Reaction
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Cope Elimination
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Cope Rearrangement
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Corey-Bakshi-Shibata Reduction
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Corey-Chaykovsky Reaction
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Corey-Fuchs Reaction
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Corey-Kim Oxidation
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Corey-Seebach Reaction
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Corey-Suggs Reagent
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Corey-Winter Olefin Synthesis
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Coumarin Synthesis
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Criegee Mechanism for Ozonolysis
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Cross Metathesis
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Curtius Rearrangement (Reaction)
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Dakin Reaction
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Darzens Condensation
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Darzens Reaction
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Delépine Reaction
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Deprotonation
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Dess-Martin Oxidation
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Diazotisation
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Dieckmann Condensation
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Diels-Alder Reaction
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Directed ortho Metalation
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Doebner Modification
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Eglinton Reaction
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Electronegativity
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Ene Reaction
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Enyne Metathesis
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Epoxidation
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Eschweiler-Clarke Reaction
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Ester Pyrolysis
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Esterification
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Favorskii Reaction
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Finkelstein Reaction
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Fischer Esterification
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Fischer Indole Synthesis
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Fleming-Tamao Oxidation
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Formal Charge
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Friedel-Crafts Acylation
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Friedel-Crafts Alkylation
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Friedlaender Synthesis
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Fries Rearrangement
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Gabriel Synthesis
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Gewald Reaction
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Glaser Coupling
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Griesbaum Coozonolysis
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Grignard Reaction
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Grubbs Reaction
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Haloform Reaction
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Hantzsch Dihydropyridine Synthesis (Pyridine Synthesis)
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Hay Coupling
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Heck Reaction
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Hell-Volhard-Zelinsky Reaction
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Henry Reaction
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Hiyama Coupling
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Hiyama-Denmark Coupling
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Hofmann Elimination
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Hofmann's Rule
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Horner-Wadsworth-Emmons Reaction
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Hosomi-Sakurai Reaction
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Huisgen Cycloaddition
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Hunsdiecker Reaction
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Hydroboration
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Ireland-Claisen Rearrangement
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Itsuno-Corey Reduction
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Iwanow Reaction (Reagent)
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Jacobsen Epoxidation
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Jacobsen-Katsuki Epoxidation
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Jocic Reaction
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Johnson-Corey-Chaykovsky Reaction
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Jones Oxidation
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Julia-Kocienski Olefination
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Julia-Lythgoe Olefination
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Kabachnik-Fields Reaction
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Keto
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Kindler Reaction
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Kinetic Control
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Knoevenagel Condensation
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Kochi Reaction
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Kolbe Electrolysis
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Kolbe Nitrile Synthesis
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Kolbe-Schmitt Reaction
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Kulinkovich Reaction
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Kulinkovich-Szymoniak Reaction
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Kulinkovich-de Meijere Reaction
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Kumada Coupling
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Lawesson's Reagent
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Leuckart Thiophenol Reaction
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Luche Reduction
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Malonic Ester Synthesis
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Mannich Reaction
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Markovnikov's Rule
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McMurry Reaction
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Meerwein-Ponndorf-Verley Reduction
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Meta
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Methyl
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Michael Addition
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Michaelis-Arbuzov Reaction
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Mitsunobu Reaction
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Miyaura Borylation Reaction
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Modified Julia Olefination
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Mukaiyama Aldol Addition
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Myers' Modification of the Ramberg-Bäcklund Reaction
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Myers-Saito Cyclization
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Nazarov Cyclization
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Nef Reaction
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Negishi Coupling
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Newman-Kwart Rearrangement
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Nitroaldol Reaction
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Nozaki-Hiyama Coupling
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Nucleophilic Substitution (SN1 / SN2)
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Ohira-Bestmann Reagent
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Olefin Metathesis
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Oppenauer Oxidation
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Ortho
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Overman Rearrangement
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Oxy-Cope Rearrangement
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Ozonolysis
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Paal-Knorr Furan Synthesis
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Paal-Knorr Pyrrole Synthesis
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Paal-Knorr Thiophene Synthesis
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Para
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Passerini Reaction
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Paterno-Büchi Reaction
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Pauson-Khand Reaction
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Pechmann Condensation
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Petasis Reaction
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Peterson Olefination
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Pinacol Coupling Reaction
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Pinacol Rearrangement
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Pinner Reaction
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Prilezhaev Reaction
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Primary (1°)
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Prins Reaction
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Prévost Reaction
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Pschorr Reaction
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Ramberg-Bäcklund Reaction
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Rate expression
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Reaction Rate
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Reformatsky Reaction
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Resonance
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Ring Closing Metathesis
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Ring Opening Metathesis (Polymerization)
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Ritter Reaction
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Robinson Annulation
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Rosenmund Reduction
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Rosenmund-von Braun Reaction
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Rubottom Oxidation
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Sakurai Reaction
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Sandmeyer Reaction
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Sarett Reagent
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Saytzeff's Rule
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Schiemann Reaction
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Schlosser Modification
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Schmidt Reaction
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Schotten-Baumann Reaction
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Secondary (2°)
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Seebach Umpolung
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Seyferth-Gilbert Homologation
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Shapiro Reaction
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Sharpless Aminohydroxylation
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Sharpless Dihydroxylation
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Sharpless Epoxidation
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Shi Epoxidation
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Simmons-Smith Reaction
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Sonogashira Coupling
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Staudinger Cycloaddition
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Staudinger Reaction
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Staudinger Reduction
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Staudinger Synthesis
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Steglich Esterification
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Steric Strain
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Stetter Reaction
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Stille Coupling
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Strecker Synthesis
...
Suzuki Coupling
...
Swern Oxidation
...
Synthesis: Alcohol to Aldehydes
...
Synthesis: Alcohol to Alkenes
...
Synthesis: Alcohol to Alkoxides
...
Synthesis: Alcohol to Alkyloxonium ions
...
Synthesis: Alcohol to Ketones
...
Tamao-Kumada Oxidation
...
Tebbe Olefination
...
Tertiary (3°)
...
Thermodynamic Control
...
Tishchenko Reaction
...
Tortional Strain
...
Trost Allylation
...
Tsuji-Trost Reaction
...
Ugi Reaction
...
Ullmann Reaction
...
Upjohn Dihydroxylation
...
Van Leusen Imidazole Synthesis
...
Van Leusen Oxazole Synthesis
...
Van Leusen Reaction
...
Vicarious Nucleophilic Substitution
...
Vilsmeier Reaction
...
Wacker-Tsuji Oxidation
...
Weinreb Ketone Synthesis
...
Wenker Synthesis
...
What is a Diels-Alder Reaction?
...
Willgerodt-Kindler Reaction
...
Williamson Synthesis
...
Wittig Reaction
...
Wittig-Horner Reaction
...
Wohl-Ziegler Reaction
...
Wolff Rearrangement
...
Wolff-Kishner Reduction
...
Woodward Reaction
...
Woodward cis-Hydroxylation
...
Wurtz Reaction
...
Wurtz-Fittig Reaction
...
Yamaguchi Esterification
...
Isobutyl
........CH₃ ........ ↑ -CH₂-CH ........↓ ......CH₃
Base (proton acceptor)
1
ortho
1,2 positions
meta
1,3 positions
para
1,4 positions
How are Radical Reactions Formed
1. Adding Energy in the form of heat or light. 2. Radical initiator, a compound that contains an especially weak bond that serves as a source of radicals. Peroxides RO-OR are most common radical initiators.
Chloronation vs. Bromination
1. Chlorination is faster than bromination. 2. Although chlorination is unselective, yielding a mixture of products, bromination is often selective, yielding one major product. **In bromination, the major product results from cleavage of the weakest C-H bond.
Goldilocks Solvents
1. DMF 2. Methanol 3. Ethanol 4. Acetone
Types of Steps in a Chemical Reaction
1. Formation of a bond (covalent) 2. Breaking of a bond (homo/heterogenic) 3. Oxidation of a functional group 4. Reduction of a functional group
Radical Addition Reactions to Double Bonds
1. HBr adds to alkenes to form alkyl bromides in the presence of light, heat, or peroxides. Br atom is added to the less substituted carbon.
What factors will help carbocation formation and therefore increase the rate of an Sn1 reaction?
1. Highly substituted carbons. 2. Polar solvents (Surround and isolate the carbocation) 3. Good leaving groups (Weak bases)
explain Hydroboration-oxidation: stereochemistry
1. Hydroboration step: occurs with syn addition (but with cycloalkenes, occurs both above and below the double bond, forming enantiomers!) 2. Oxidation step: occurs with retention of configuration
Steps in Radical Addition
1. Initiation- Abstraction of H from Hbr occurs by a two step process. Roor in reaction requires to steps in order to form Br- from HBr 2. Propagation- The PIE bond is broken and the C-H and C-BR sigma bonds are foremed. 3. Two radicals react to form a bond.
The Steps of Radical Halogenation
1. Initiation: Two radicals are formed by homolysis of a sigma bond and this begins the reaction. 2. Propagation: A radical reactions with another reactant to form a new sigma bond and another radical. HCL produced. Ch3 Ch2. is formed. 3. Termination: Two radicals combine to forma stable bond. Removing radicals from the reaction mixture without generating any new radicals stops the reaction.
Three Facts about halogenation that suggest the mechanism involves radical, not ionic, intermediates.
1. Light, heat, or added peroxide is necessary for the reaction. 2. O₂ inhibits the reaction. 3. No rearrangement are observed.
Two Main Reactions of Radicals
1. They react with sigma bonds. A radical X abstracts a hydrogen atom from a C-H sigma bond to form H-X and a carbon radical. 2. They add to Pie bond. A radical X adds to the Pie bond of a carbon- carbon double bond. One electron from the double bond is used to form a new C-X bond, and the other electron remains on the other carbon originally part of the double bond.
Nomenclature: what to do when there are 2 double bonds?
1. number longest chain that includes both double bonds. 2. use di-ene, tri-ene, etc suffix
explain how to determine degree of unsaturation.
1. number of carbons times 2 plus 2. 2. Subtract the actual number of H's; 3. subtract number of halogens. 4. add 1 for each Nitrogen. 5. divide total by 2. ignore oxygen.
Things to know about titration of amino acids...
1.Buffering capacity is greatest at the Ka's 2. Two moles of base need to be added in order to deprotonate one mole of most a.a. 3. When adding base, the carboxyl group looses the H first. 4. Titrations can be done in reverse starting with a basic solution and adding acid.
Acid (proton donor
2
explain Hydro-halogenation mechanism
2 step addition. 1. pi bond attacks the H of the H-X , forming an intermediate carbocation. this step is. Rate-determining. 2. the left over X- Nucleophile attacks the carbo cation, forming the new C-X bond.
TNT
2,4,6-trinitrotoluene, the 3 nitro groups give explosive properties
Conjugate acid
3
How many moles of acid are needed to neutralize 1 mole of a basic amino acid?
3 moles because of the extra R amino group.
-NO2, -SO2, -CN
3 possible deactivating groups
triol
3OH
1
3abe3 the 3ew5s ac5d
-OH2, -NH2, -OR, -NR2, alkyl
5 possible activating groups
Carbonyl Group
>C=O Occurs in two closely related families of compounds: Aldehydes and Ketones.
Grignard Reagent + CO₂ =
A Grignard reagent reacts with carbon dioxide to produce a carboxylic acid. Grignard Reagent + CO₂ --> COOH
Acid Chloride + H₂/Pd/C =
A acid chloride reacts with H2/Pd/C to produce an aldehyde. Acid Chloride + H₂/Pd/C --> Aldehyde
monosubstituted
A benzene with one additional group is....
disubstituted
A benzene with two additional groups is...
Stereo Isomers
A carbon that has 4 different things attached to it is considered "chiral" There is a mirror image of the molecule, they are stereoisomers or enantiomers, bend light oppositely (optically active)
Carboxylate Ion + Ethyl Iodide =
A carboxylate ion reacts with ethyl iodide to produce an ester. COO⁻ + Ethyl-I --> Ester
Carboxylic Acid + LiAlH₄ =
A carboxylic acid reacts with LiAlH₄ to produce a primary alcohol COOH + LiAlH₄ --> 1⁰OH
Carboxylic Acid + Alcohol =
A carboxylic acid reacts with an alcohol (e.g. ethanol) to produce an ester COOH + OH --> Ester
Carboxylic Acid + Base =
A carboxylic acid reacts with base to produce a carboxylate anion. COOH + OH⁻ --> COO⁻
Amino Acid
A carboxylic acid that contains an amino acid as well as a carboxyl group.
Ziegler-Natta Catalyst
A catalyst containing titanium tetrachloride and triethylaluminum which is used to ensure that polymers are stereoregular.
Radical Initiator
A compound that contains an especially weak bond that serves as a source of radicals.
Antioxidant
A compound that stops an oxidation reaction from occurring.
Diol
A compound with two hydroxy groups. ex. ethylene glycol, used as antifreeze.
Graft Copolymer
A copolymer consisting of a long chain of one monomer with shorter side chains of another monomer attached as side groups.
Block Copolymer
A copolymer in which a long segment of one monomer is followed by a block of another monomer.
Random Copolymer
A copolymer in which different monomers are linked in no particular order.
Alternating Copolymer
A copolymer where the differing subunits alternate.
aromatic compound
A cyclic hydrocarbon with delocalised pi electrons
Zwitterion
A form of a molecule in which a basic part has been protonated and an acidic part deprotonated; in an amino acid, the amino group would have been protonated and the carboxyl group deprotonated.
hydroxyl group
A functional group consisting of a hydrogen atom joined to an oxygen atom by a polar covalent bond. Molecules possessing this group are soluble in water and are called alcohols.
Substitution Reaction
A halogen is added to a hydrocarbon; first goes for a tertiary, then secondary, then primary.
Ketone + NaBH₄ =
A ketone reacts with NaBH₄ to produce a secondary alcohol Ketone + NaBH₄ = 2⁰ OH
Ketone + Grignard Reagent =
A ketone reacts with a Grignard reagent to produce a tertiary alcohol Ketone + Grignard Reagent = 3⁰ OH
Chain mechanism
A mechanism like radical halogenation that involves two or more repeating steps where each propagation step involves a reactive radical abstracting an atom from a stable bond to form a new bond and another radical that continues the chain. Repeat propagation can occur thousands of times before termination occurs.
Chain Mechanism
A mechanism that involves two or more repeating steps.
3
A meta substituent of a benzene is in position ___ relative to the primary substituent
Peptide
A molecule formed by the condensation of two or more amino acids.
Chiral molecule
A molecule that is not identical to its mirror image; all chiral molecules are optical isomers.
Nitrile + LiAlH₄ =
A nitrile reacts with LiAlH4 to produce an amine. Nitrile + LiAlH₄ --> Amine
Nitrile + H⁺/H₂O =
A nitrile reacts with aqueous acid to produce a carboxylic acid. Nitrile + H⁺/H₂O --> COOH
4
A para substituent of a benzene is in position ___ relative to the primary substituent
Oligopeptide
A peptide containing only a few amino acids.
Dipeptide
A peptide with only two residues.
Polyamides
A polymer formed from the condensation polymerization of amines with carboxylic acids. Commoly known as nylons.
Thermoplastic Polymer
A polymer that can be softened again after having been molded.
Thermosetting Polymer
A polymer that cannot be remolded after taking on a hardened shape.
Primary Alcohol + CrO₃/Pyridine =
A primary alcohol reacts with CrO3/pyridine to produce an aldehyde 1⁰OH + CrO3/Pyridine --> Aldehyde
Primary Alcohol + HBr =
A primary alcohol reacts with HBr to produce an alkyl halide 1⁰OH + HBr --> Alkyl Halide
1⁰ Alcohol + KMnO₄ -->
A primary alcohol reacts with KMnO₄ to produce a carboxylic acid 1⁰ Alcohol + KMnO₄ --> COOH
Addition Polymerization
A process in which alkenes react with themselves to form long chains.
Functionalization
A process in which reactive groups of atoms are introduced to alkanes.
quaternary Structure
A protein structure in which neighboring polypeptide units stack together in a specific arrangement.
Radical Polymerization of Alkenes
A radical addition mechanism is followed.
Propagation
A radical reacts with another reactant to form a new sigma bond and another radical.
Electrophile
A reactant that is attracted to regions of high electron density.
Nucleophile
A reactant that seeks out centers of positive charge in a molecule.
Substitution Reaction
A reaction in which an atom or group of atoms replaces an atom (in alkanes, a H atom) in the original molecule.
Addition Reaction for Alkenes
A reaction in which atoms supplied by the reactant form σ-bonds to the two atoms originally joined by the double bond.
Hydrohalogenation
A reaction in which halogens are added.
Hydrogenation Reaction
A reaction in which hydrogens are added.
Elimination Reaction
A reaction in which two groups or atoms on neighboring carbon atoms are removed from a molecule, leaving a multiple bond.
Condensation Reaction
A reaction in which two molecules combine to form a larger one and a small molecule, usually water, is eliminated. The reaction can be catalyzed by a small amount of strong acid.
Radical
A reactive intermediate with a single unpaired electron, formed by homolysis of a covalent bond. Contains an atom that does not have an octet of electrons, making it reactive and unstable.
What is an amino acid called after it becomes a part of a peptide?
A residue.
notes
A rule to keep in mind is that charge delocalization is always a stabilizing factor
2⁰ OH + Na₂CrO₇ (or CrO₃/Pyridine) =
A secondary alcohol reacts with Na2CrO7 or CrO3/pyridine to produce a ketone 2⁰ OH + Na₂CrO₇ (or CrO₃/Pyridine) > Ketone
Condensed Structural Formula
A simple way of writing out the formula of hydrocarbons that shows how the atoms are grouped. ex. CH₃CH₃(CH₃)CH₃
Geometric Isomers
A stereoisomer in which the atoms have different arrangements on either side of a double bond or above and below the ring of a cycloalkane or cycloalkene. Geometrical isomers are distinguished by the prefixes cis- and trans-.
Elasticity
A substance's ability to return to its original shape after being stretched.
ortho
A substituent of a disubstituted benzene that is next to the primary substituent
para
A substituent of a disubstituted benzene that is three down from the primary substituent
meta
A substituent of a disubstituted benzene that is two down from the primary substituent
deactivating group, meta director
A substituent of an aromatic compound that slows down electrophilic substitution
activating group, O-P director
A substituent of an aromatic compound that speeds up electrophilic substitution
Monomer
A subunit of a polymer.
What free radical is most is likely to be formed from bromination?
A tertiary radical (Most stable)
Quaternary Ammonium Ion
A tetrahedral ion of the form R₄N⁺.
benzyl
A toluene as a substituent without a hydrogen on its methyl group is called a ____ group
Nucleoside
A unit consisting of a nitrogenous base and a ribose sugar.
Nucleotide
A unit consisting of a nitrogenous base, ribose sugar, and phosphate group.
Dehydrohalogenation
A way of producing alkenes by the removal of a hydrogen atom and a halogen atom from neighboring carbon atoms.
Achiral Chiral
A- Always gives either an achiral or a racemic product. C- If a rection does not occur at a stereogenic center, the configuration at a stereogenic center is retained. If new stereogenic center is created then diastereomers are formed. If rx occurs at stereo center, teh we must know the mechanism to predict the stereochemistry.
When is vacuum filtration used?
ABOVE 150 C BOILING POINTS! Vacuum will lower the pressure of the apparatus to ensure that the liquids do not decompensate under the extreme temperatures.
Nucleophilic Addition of Amines to Aldehydes/Ketones: Imine and Enamine Formation
Acid Catalyzed|- If pH I too low product will not form. Optimal pH ~4.5|- Through a Carbinolamine Intermediate
Acid Chloride +1⁰/2⁰ Amine =
Acid Chloride reacts with 1⁰ or 2⁰ Amine to produce an Amide Acid-Cl + 1⁰ or 2⁰ Amine --> Amide
Acid Chloride + Alcohol =
Acid Chloride reacts with an Alcohol (e.g. ethanol) to produce an Ester Acid Chloride + OH --> Ester
Acid Chloride + (2x) Grignard Reagent =
Acid chloride reacts with a Grignard Reagent to produce a 3⁰ Alcohol Acid-Cl + (2x) Grignard Reagent --> 3⁰ Alcohol
Esterification/Condensation Reactions
Acid+Alcohol→Ester+H₂O ( O ) ( || ) ( C - O ) (Always have a C double bonded to an O and single bonded to another O in the middle of the molecule ((↑)O=C-O)
When carbonyl's are attacked by hydrolysis, what does the nucleophile look like in acidic vs basic conditions?
Acidic: H₂O is attacking Basic: OH- is attacking In acidic conditions the carbonyl oxygen is protonated.
...
Acidity increases from left to right when we compare compounds in a given row of the periodic table.
What is the order of reactivity for carboxylic acid derivatives?
Acyl halide > anhydrides > esters > amides
RCOCL/AlCl₃
Acylation
Alpha Halogenation of Aldehydes and Ketones
Add heat in pyridine solvent to remove halogen leaving C=C
Types of Organic Reactions (4)
Addition - 2 Molecules combine Elimination - One molecule splits Substitution - exchange portions of molecules Rearrangement - Connections between atoms change
define Halogenation. what is added?
Addition of 2 chlorines or 2 bromines to an alkene. forming a vicinal dihalide (X atoms are on the same side).
explain Hydration stereochemistry
Addition of H and OH occurs in Both syn and anti directions, potentially forming 4 stereoisomers.
How do you form an ester with a carboxylic acid?
Addition of a primary alcohol under ACIDIC conditions.
define Hydration. what does it produce? what are common methods?
Addition of water to an alkene to form an alcohol. can use acid catalyzed or hydro boration.
Addition of Grignards to Ethylene Oxide
Adds -CH2CH2OH|Acyclic and larger ring ethers do not work
what does Hydro-halogenation add? is it endo or exo thermic?
Adds Hydrogen and Chloride, bromide or Iodide. Exothermic!
Hydrolysis of Nitriles|(Formation of a Carboxylic Acid through Nitrile from an Alkyl Halide)
Adds carbon
How do you get glycosides from your hemiacetal monosaccharide?
Alcohol in the presence of ACID!!
Dehydration Reactions/Ether
Alcohol+Alcohol→Ether+H₂O (Have the formula R-O-R')
19.7 Esters Summary
Alcohols condense with carboxylic acids to form esters.
Carbonyl Condensation: The Aldol Reaction
Aldehyde R group: CH3/1° - product favored, 2°/3° product not favored (sterics)|Product is always unfavored with ketones
19.5 Aldehydes and Ketones Summary
Aldehydes and ketones can be prepared by the oxidation of alcohols. Aldehydes can be more easily oxidized than ketones can.
Systematic names for aldehydes and ketones
Aldehydes are named by replacing the ending -e with -al, ex methane → methanal. Ketones are named using the suffix -one.
Types of Aliphatic Hydrocarbons
Aliphatic hydrocarbons are distinguished from one another by the types of bonds between carbons; the bonds determine what sorts of reactions a hydrocarbon can undergo.
18.4 Alkane Substitution Reactions Summary
Alkane substitution takes place by a radical chain mechanism.
Cycloalkanes
Alkanes that contain rings of carbon atoms.
Haloalkanes, aka Alkyl Halides
Alkanes with at least one hydrogen atom replaced with a halogen atom.
Addition Reaction
Alkene+Small molecule→Saturated Compound
19.9 Addition Polymerization Summary
Alkenes undergo addition polymerization. When a Ziegler-Natta catalyst is used, the polymer is stereoregular and has a high density.
RCl/AlCl₃
Alkylation
true
All Lewis acids are electrophiles
Monosaccharide ester formation
All hydroxyl groups will be esterified!
How does isoelectric focusing work?
All proteins have an isoelectric point (no charge). When the molecule reaches the field that is equal to its isoelectric point, it will stop moving!
Aliphatic Compounds
All shared electrons are held specifically to the bonding atoms
Amide + LiAlH₄ =
Amide reacts with LiAlH₄ to produce an Amine Amide + LiAlH₄ --> Amine *(REDUCTION)
Amide Formation
Amine+Acid→Amide+Water (Amides always have -NH-C=O(↑) in the middle)
19.8 Amines, Amino Acids, and Amides Summary
Amines are derived from ammonia by the replacement of hydrogen atoms with organic groups. Amides result from the condensation of amines with carboxylic acids. Amines and many amides take part in hydrogen bonding.
Amine nomenclature
Amines are named by specifying the groups attached to the nitrogen atom in alphabetical order followed by the suffix -amine. Amines with two amino groups are called diamines. The -NH₂ group is called amino- when it is a substituent.
α-amino acids
Amino acids in which the -NH₂ group is attached to the carbon atom next to the carboxyl group, ex. glycine, NH₂CH₂COOH.
Amylose/Amylopectin
Amylose consists of chains of several thousand glucose molecules. Amylopectin consists of chains of glucose molecules with branches. Each molecule contains ~1 million glucose.
Acetal + aqueous Acid =
An acetal reacts with aqueous acid to produce an aldehyde Acetal + aqueous Acid --> Aldehyde
Acid Chloride + NaBH₄ =
An acid chloride reacts with NaBH₄ to produce a primary alcohol. Acid Chloride + NaBH₄ --> 1⁰OH
Aldehyde + KMnO₄ =
An aldehyde reacts with KMnO₄ to produce a carboxylic acid. Aldehyde + KMnO₄ --> COOH
Aldehyde + NaBH₄ =
An aldehyde reacts with NaBH₄ to produce a primary or secondary alcohol. Aldehyde + NaBH₄ --> 1⁰ or 2⁰ OH
Aldehyde + Grig. Reagent / Ether
An aldehyde reacts with a Grignard reagent and ether to produce a secondary alcohol Aldehyde + Grignard Reagent+Ether --> 2⁰ OH
Aldehyde + 1⁰ Amine =
An aldehyde reacts with a primary amine to produce an imine Aldehyde + 1⁰ Amine --> Imine
Aldehyde + alcohol and acid =
An aldehyde reacts with an alcohol (e.g. ethanol) and acid to produce an acetal. Note that using with less EtOH/H+, a hemiacetal will form Aldehyde + alcohol and acid (x2) = Acetal Aldehyde + alcohol and acid (x1) = Hemiacetal
Aldehyde + aqueous NaCN =
An aldehyde reacts with aqueous NaCN
Unsaturated Hydrocarbon
An aliphatic hydrocarbon containing at least one multiple bonds.
Saturated Hydrocarbon
An aliphatic hydrocarbon containing only single bonds.
Alkyl Halide + Mg/Ether =
An alkyl halide reacts with Mg/ether to produce a Grignard reagent. Alkyl Halide + Mg/Ether --> Grignard Reagent
Alkyl Halide + NaCN =
An alkyl halide reacts with NaCN to produce a nitrile. Alkyl Halide + NaCN --> Nitrile
What is hofmann rearrangement?
An amide to a primary amine (Pg 389)
Carbocation
An electrophilic intermediate capable of accepting an e- pair
Ester + LiAlH₄ =
An ester reacts with LiAlH4 to produce a primary alcohol. Ester + LiAlH₄ --> Primary Alcohol
Ester + (2x) Grignard Reagent =
An ester reacts with a Grignard reagent to produce a tertiary alcohol. Ester + (2x) Grignard Reagent --> Tertiary Alcohol
Br+
An example of a powerful electrophile
Halogenation
An example of an addition reaction; the addition of two halogen atoms at an alkene's double bond.
Imine + NaBH₄ =
An imine reacts with NaBH4 to produce a secondary amine. Imine + NaBH₄ --> 2⁰Amine
Disulfide Link
An important link found in tertiary structures; -S-S-
tritium
An isotope of hydrogen that contains one proton and two neutrons per atom.
Amine
An organic compound containing NH₃. Amines are classified according to the number of R groups on the nitrogen: - Primary: RNH₂ - Secondary: R₂NH - Tertiary: R₃NH In all cases the N atom is sp³ hybridized.
Alcohol
An organic compound containing a hydroxyl group not connected directly to a benzene ring or to a >C=O group.
Ether
An organic compount of the form R-O-R.
carbocation
An organic ion in which a carbon atom has a positive charge
Phenol
An organic molecule containing a hydroxyl group attached directly to an aromatic ring. Many occur naturally and are often components of essential oils.
2
An ortho substituent of a benzene is in position ___ relative to the primary substituent
Reaction Mechanism
An overall description of how a particular reaction occurs.
Arenes
Another name for aromatic hydrocarbons; they contain an aromatic ring, often benzene.
Addition of halogens Cl2 and Br2
Anti addition is observed through a halonium ion intermediate
Hydroxylation by acid-catalyzed epoxide hydrolysis
Anti stereochemistry occurs
Carboxylic Acids
Are made by oxidizing aldehydes (-C-OH) ( || ) ( O ) End in -oic
Ketones
Are made by oxidizing secondary alcohols (-OH on a non-end carbon; can't oxidize any further)
18.7 Nomenclature of Arenes Summary
Aromatic compounds are named by giving the substituents on the benzene ring the lowest numbers. When the benzene ring itself is named as substituent, it is called a phenyl group.
Friedel Crafts Acylation
Aromatic ring acylated through electrophillic aromatic substitution.
18.8 Electrophilic Substitution Summary
Aromatic rings are much less reactive than their double-character would suggest; they commonly undergo substitution rather than addition. Electrophilic substitution of benzene with electron-donating substituents is accelerated and takes place at the ortho and para positions preferentially. Electrophilic substitution of benzene with electron-withdrawing substituents takes place at a reduced rate and primarily at the meta position.
phenyl, aryl
As a substituent, an aromatic ring is called either a ___ or a ___ group
Heterolytic Cleavage
Asymmetrical distribution of electrons after bond breaking.
When does an amino acid take on the zwitterion form?
At the isoelectric point or isoelectric pH between pKa₁ and pKa₂
What kind of bond does Cellulose have vs Starch and glycogen?
BETA 1, 4 vs the ALPHA of starch and glycogen (some α 1,6 in there too!)
How do Agrose gel and SDS-PAGE electrophoresis separate molecules?
Based on SIZE
true
Because oppositely charged ions attract each other, their separation requires considerable energy..Heterolysis requires separation of oppositely charged ions.
Polymer properties
Because synthetic polymers consist of chains of varying lengths, there can only be averages - average chain lengths, molar masses, etc. Properties are from averages.
notes
Because the concentrations of the products of the reaction are written in the numerator and the concentration of the undissociated acid in the denominator, a large value of Ka means the acid is a strong acid and a small value of Ka means the acid is a weak acid.
False vice versa
Because the concentrations of the products of the reaction are written in the numerator and the concentration of the undissociated acid in the denominator, a large value of Ka means the acid is a weak acid and a small value of Ka means the acid is a strong acid.
Phenyl Group
Benzene as a functional group
Toluene
Benzene ring with -CH₃
Phenol
Benzene ring with -OH
Aniline
Benzene ring with NH₂
phenol
Benzene ring with an OH group directly attached to it
xylene
Benzene with two methyl groups in ortho, para, or meta positions
...
Bond strength to the proton decreases as we move down the column, increasing its acidity.
Secondary Carbon
Bonded to 2 other carbons
Tertiary Carbon
Bonded to 3 other carbons
H, NBS, CCl₄
Br replaces __. Reaction occurs with ____ over ____.
OH, PBr₃, ether
Br replaces __. Reaction occurs with ____ over ____.
4 Carbons
But-
Addition of water to Alkenes
By Oxymercuration: Markovnikov addition|By Hydroboration: Anti-Markovnikov addition
ether
C-O-C, a compound containing an oxygen bonded to 2 carbon atoms
phenyl group
C6H5-, Benzene ring attached to a parent compound
benzene
C6H6, leukemia
Tert-Butyl
CH₃ ↑ -C-CH₃ ↓ CH₃
Carbon Radical
Can be primary to tertiary depending ont he amount of R groups. A carbon radical is sp² hybridized and trigonal planar.
19.14 Carbohydrates Summary
Carbohydrates include sugars, starches, and cellulose. Glucose is an alcohol and an aldehyde that polymerizes to form starch and cellulose.
Aromatic Compounds
Carbon rings with alternating single/double bonds
COOH + SOCl₂/PCl₅ =
Carboxylic Acid reacts with SOCl₂ or PCl₅ to produce an Acid Chloride COOH + SOCl₂ or PCl₅ --> Acid Chloride
False.....Carboxylic acids are weak acids
Carboxylic acids are strong acids
The production of carboxylic acids
Carboxylic acids can be prepared by oxidizing primary alcohols and aldehydes with a strong oxidizing agent; in some cases an alkyl group can be oxidized directly to a carboxyl group.
19.6 Carboxylic Acids Summary
Carboxylic acids have an -OH group attached to a carbonyl group to form the carboxylic group, -COOH.
What is the purpose of Infrared (IR) spectroscopy?
Certain bonds absorb infrared light at different frequencies and this can then be measured through what is absorbed vs what is transmitted. Used for FUNCTIONAL GROUP identification.
Naming Esters
Change the -anol of he alcohol to -yl and the -oic acid of the parent acid to -oate. CH₃COOCH₃ Methanol + Ethanoic Acid → Methyl Ethanoate
OH, SOCl₂, Pyridine
Cl replaces __. Reaction occurs with ____ over ____.
18.10 Coal Summary
Coal is primarily aromatic in nature.
Naming single-chain alkanes.
Combine a prefix denoting the number of carbon atoms with the suffix -ane.
arene
Compound derived from benzene
Acidity of Alpha Hydrogens
Compound ~ pKa Alkanes ~ 60 Esters ~ 25 Ketones ~ 19 Aldehydes ~ 17 Acid Halides ~ 16 1,3 Diketones ~ 9 Carboxylic Acids ~ 5
Hydrocarbons
Compounds built from only carbon and hydrogen.
Radical Inhibitors
Compounds that prevent radical reactions from occurring.
Peroxides
Compounds with the general structure RO-OR, the most common radical indicators.
Rearrangement
Connections between atoms change Products and reactants are isomers (CH3CH2)CH=CH2 --> (CH3)CH=CH(CH3)
19.11 Copolymers Summary
Copolymers combine the advantages of more than one component material.
Crown Ethers
Cyclic ethers with alternating -CH₂CH₂-O- units; named for their crownline structure.
10 Carbons
Dec-
Substituents in a molecule; prefixes, and how to arrange them
Di, tri, tetra, penta, hexa, etc. Numbers set off by hyphens specify to which carbon atoms the groups are attached, ex. 1-Ethyl-2-methylcyclopentane. Substituents are listed in alphabetical order, disregarding the prefixes.
What are epimers?
Diastereomers that differ in the configuration of ONE carbon.
Nucleophilic Addition of Alcohols to Aldehydes/Ketones
Diols can be used to protect carbonyl groups
Prion Diseases
Diseases caused by the infectious misfolding of proteins.
Three classes of alcohol
Divided by the number of organic groups attached to the carbon atom connected to the -OH group: - Primary; one R group - Secondary: two R groups - Tertiary: 3 R groups; often shortened to "tert"
Why ortho and para are preferred
Draw a benzene, look at the resonance structure and where negative charges would be placed.
in which reactions are carbo cations intermediates not formed
E2. SN2. Hydro-boration. halo hydrin formation. Halogenation
Lewis base
Electron pair donor
What are nucleophiles?
Electron-rich species that are attracted to a positively polarized atom (i.e. a carbonyl carbon)
Synthesis: How do you prepare an alkene?
Elimination reaction - dehydrohalogenation - dehydration
2 Carbons
Eth-
19.3 Ethers Summary
Ethers are not very reactive. They are more volatile than alcohols with similar molar masses because their molecules cannot form hydrogen bonds with one another. Crown ethers adopt shapes that can enclose ions and carry them into nonpolar solvents.
Ethanol, aka...
Ethyl alcohol, grain alcohol.
Lipophobic (Hydrophilic) Antioxidants
Examples: 1. ascorbate 2. uric acid
Lipophilic (Hydrophobic) Antioxidants
Examples: 1. α-tocopherol 2. ubiquinone 3. carotenes
Substitution
Exchange of pieces of molecules CH3Br + KOH --> CH3OH + KBr
Methane and Cl₂
Exothermic. Because the rate-determining step in chlorination is exotermic, the transition sate resembles the starting material, both radicals are formed, and a mixture of products results.
Saturated lipids are more easily oxidized than saturated ones resulting in eventual rancid smell
False. Unsaturated.
Carboxylic acid Alcoholysis
Fischer Esterification
Ester Preparation
Fischer Esterification is a type of Alcoholysis involving Carboxylic acids.|Esters can also be made by Alcoholysis of Acid halides and Acid anhydrides
What is a better nucleophile I or F?
Flourine
How do you make OH- a good leaving group for Sn1 and Sn2 reactions?
For Sn1 you can protonate it and make water the leaving group. For Sn2 you can convert it to tosylate which is also a good leaving group.
Nucleophilic Substitution
For haloalkanes, a substitution in which a nucleophile replaces the halogen atom.
Acid anhydride Hydrolysis
Forms Carboxylic acids
How do you get a disaccharide?
From the same reaction that gave us the glycoside! Its just that now the alcohol is.....ANOTHER MONOSACCHARIDE! YAY!
How what is Gabriel Synthesis for?
Gabriel drank ammonia! OH NO!
What is the only amino acid that is NOT CHIRAL?
Glycine
Gravity filtration vs vacuum filtration
Gravity filtration is used for when the desired product is in solution (usually hot) where as vacuum filtration has the desired product being a solid.
When numbering atoms in the chain, the lowest numbers are given preferentially to:
Groups of atoms named by suffixes Double bonds Triple bonds Groups named by prefixes
Why polyester molecules make good fibers
Growth can only occur at the functional groups, so chain branching is much less likely, keeping the polymers linear.
Br
H replaced with __.
Reduction of Nitriles (cyano group) to form an Amine
H: adds to carbon twice the N(-2) is protonated by water
19.1 Haloalkanes Summary
Haloalkanes are alkanes in which at least one hydrogen atom has been replaced by a halogen atom; they undergo nucleophilic substitution.
X₂/FeX₂
Halogenation
In which mechanisms can anti addition occur?
Halogenation and Halohydrin formation do only anti....but... Hydration and Hydro-halogenation do syn and anti. in the mechanisms with halonium ion/ the ones involving Xs with. Think about how this looks.
Synthesis: How do you form a halohydrin (alkane chain with an -OH and an -X)? Where do the additives go, and how are they arranged?
Halohydrin formation. OH goes to most substituted. Halogen goes to least substituted. they are anti. oriented.
Amine
Have -NH2 in them
Ketones
Have a carbonyl (C=O) group in the molecule. End in -one
Aldehydes
Have a carbonyl group on the end carbon. End in -al. Are made by oxidizing primary alcohols (-OH on end carbon)
Alcohols
Have a hydroxyl group (-OH). End in -ol
Unsaturated Hydrocarbons
Have double or triple bonds (they can react and get more atoms in the molecule; alkenes and alkynes)
7 Carbons
Hept-
Names of common alkanes (7-12)
Heptane : CH₃(CH₂)₅CH₃ Octane : CH₃(CH₂)₆CH₃ Nonane : CH₃(CH₂)₇CH₃ Decane : CH₃(CH₂)₈CH₃ Undecane : CH₃(CH₂)₉CH₃ Dodecane : CH₃(CH₂)₁₀CH₃
6 Carbons
Hex-
What are the reagents for Clemmensen Reduction?
Hg(Zn) and HCl
Volatility of Alcohols
Higher than hydrocarbons of the same mass due to their ability to form H-bonds.
Carbohydrates
Hydrates of carbon.
Synthesis: 2 ways to prepare an alcohol?
Hydration and Hydro-boration-oxidation
We have 3 reactions that add OH to an alkene. In which reaction does the OH get added to the least substituted carbon.
Hydro boration. the OH goes to the least substituted carbon.
In which mechanisms can Syn addition occur?
Hydroboration does syn only...but...... Hydration and Hydro-halogenation do syn and anti remember: it is boring to be the same.
Hydration of Terminal Alkynes
Hydroboration/Oxidation yields an Aldehyde|Mercury(II)-Catalyzed hydration yields a methyl ketone
Alkenes
Hydrocarbons containing at least one carbon-carbon double bond.
Alkynes
Hydrocarbons containing at least one carbon-carbon triple bond.
Alkene
Hydrocarbons with at least one double bond. (CnH₂n)
Alkyne
Hydrocarbons with at least one triple bond.
Phenol Group
Hydroxy Group bonded to a benzene ring.
Reduction of acyl halide?
H₂ Pd/BaSO₄ Quinoline
What are the reagents for Wolff-Kishner Reduction of al and ke?
H₂NNH₂, then a base and heat.
Dehydration of Beta-hydroxy carbonyl compounds (aldol products):|Synthesis of Enones
If heat isn't shown give aldol product (resonance structure)
Iodoform Test - for methyl ketones
If yellow ppt. (HCI3) appears then methyl ketone present
electrophile
In electrophilic aromatic substitution, this replaces a hydrogen in the original molecule
How the carbonyl group is written in different situations
In ketones, it is written as -CO- In aldehydes, it is written as -CHO
M
In the presence of a deactivating group, the electrophile is most likely to be added at this position
O, P
In the presence of an activating group, the electrophile is most likely to be added at this position
Halogenation of Alkanes
In the presence of light or heat, alkanes react with halogens to form alkyl halides. This is a radical substitution reaction that is only useful with Cl₂ and Br₂ not F₂.
true
Inductive effects weaken steadily as the distance between the substituent and the acidic group increases
Steps in a radical chain mechanism
Initiation Propagation Termination
positive charge stabilised by resonance
Intermediate step in an electrophilic substitution reaction
What is a better leaving group I or F?
Iodine
Column Chromatography
Ion Exchange Chromatography Size-Exclusion Chromatography Affinity Chromatography
How can you think of Lithium Aluminum Hydride?
It is like an H- nucleophile.
What doesn't a nucleophile play a role in the rate of an Sn1 reaction?
It is not involved in the rate-determining step...the formation of the carbocation.
What role does tosylate usually play in reactions?
It usually acts as a good leaving group and a good protecting group.
Why is a Sn2 reaction bimolecular?
Its rate-determining step is dependent on TWO species; both the substrate and the nucleophile.
Polymerization
Joining together of monomers to make polymers
What oxidizes an aldehyde and what do you get?
KMnO₄, CrO₃, Ag₂O, H₂O₂ and you get a carboxylic acid.
acidity constant
Ka
What reduces aldehydes and ketones?
LAH or NaBH₄
Reactivity-Selectivity Principle
Less reactive reagents are more selective.
Linear vs branched chain packing
Linear chains can pack more tightly than branched ones, so materials with aligned linear chains tend to be dense and tough.
Enolate Alkylation
Lithium diisopropylamide (LDA) can be used to form enolate
Parent Chain
Longest carbon chain
Do ethers boil at high or low temperatures?
Low...no H-bonding.
Polymers
Macromolecular compounds in which chains or networks of small repeating units form giant molecules. They are made mainly by addition and condensation reactions.
Polyamides
Made from diamines and diacids (Amine + Acid > Amide + H2O) (Condensation reaction)
Properties of haloalkanes
Many a highly toxic; many pesticides are aromatic compounds with several halogen atoms.
Properties of Esters
Many esters are fragrant and contribute to the flavor of fruits. Other esters are oils or fats.
true
Many of the reactions that occur in organic chemistry are either acid-base reactions themselves or they involve an acid-base reaction at some stage
Halohydrin formation
Markovinkov regiochemistry (water on more substituted) and anti stereochemistry occurs
Addition of water by oxymercuration-demurcuration
Markovnikov regiochemistry occurs
Addition of HCl,HBr,and HI
Markovnikov regiochemistry occurs, with H adding to the less highly substituted alkene carbon and the halogen adding to the more highly substituted
1 Carbon
Meth-
Names of common alkanes (1-6)
Methane : CH₄ Ethane : CH₃CH₃ Propane : CH₃CH₂CH₃ Butane : CH₃(CH₂)₂CH₃ Pentane : CH₃(CH₂)₃CH₃ Hexane : CH₃(CH₂)₄CH₃
Achiral Molecule
Molecules that are not chiral.
Conformations
Molecules that are not isomers, but that may appear so due to the rotation of the orientation of the depicted molecule.
Stereoisomers
Molecules with the same formula and their constituent atoms connected the same, but arranged differently in space. Consists of two kinds: geometric, and optical.
Structural Isomers
Molecules with the same formula but with their constituent atoms connected differently
Polyester
Monomers are "diacid" and "diol" (Acid + Alcohol > Ester + H2O *Chain*) (Condensation reaction)
Volatility of Ethers
More volatile than alcohols of the same molar mass because they do not form H-bonds to one another; also less soluble in water for the same reason.
19.10 Condensation Polymerization Summary
Most condensation polymers are formed by the reaction of a carboxylic acid with an alcohol to form a polyester or with an amine to form a polyamide.
Oxidation of Ketones to form two Carboxylic acids
Most practical for symmetrical ketones
Radical Halogenation at an Allylic Carbon (Carbon adjacent to a double bond).
Most stable***Smallest Delta H. The true structure of the allyl radical is a hybrid of the two resonance structures. In the hybdi, the PIE bond and the unpaired electron are delocalized. Delocalizing electron density lowers the energy of teh hybrid, thus stabilizing the allyl radical.
Benzene Ring
Most well known aromatic compound. Stable because electrons aren't held in their positions; the pi electrons are delocalized and shared among all bonded carbons.
NBS
N-Bromosuccinimide. Selectively halogenates the weaker allylic C-H bonds.
what can NBS in DMSO do?
NBS is a source of Bromine. Forms a bromohydrin (halohydrin);
Naming halides
Name the halogen atom as a substituent by changing the -ine to an -o, ex. 2-chlorobutane.
HNO₃/H₂SO₄
Nitration
Acid halide Preparation
No mechanism needed
Carboxylic acid Aminolysis
No mechanism needed
notes
No resonance structures can be drawn for either ethanol or ethoxide anion.
9 Carbons
Non-
Functional Group
Non-H branches (Ex; methyl group)
Addition of water by hydroboration-oxidation
Non-Markovinkov syn addition occurs
19.15 Nucleic Acids
Nucleic acids are copolymers of four nucleotides joined by phosphate ester links. The nucleotide sequence stores all genetic information.
Ring Opening of Epoxides - Acid catalyzed
Nucleophile adds to less hindered carbon (Sn2-like) unless a 3° Carbon is available (Sn1-like)
anisole
OCH3 attached to a benzene ring
Br
OH replaced with __.
Cl
OH replaced with __.
X
OH replaced with __.
8 Carbons
Oct-
The difference between oligo and polysaccharide?
Oligo is short poly is long.
Where do you start numbering a carbohydrate?
On the carbonyl end.
Primary Carbon
On the end of the chain
Elimination Reaction
One molecule splits into pieces CH3CH2Br --> H2C=CH2 + HBr
Aromatic Hydrocarbons
One of two broad classes of hydrocarbons. Contains a benzene ring as part of its molecular structure.
Aliphatic Hydrocarbon
One of two broad classes of hydrocarbons. Does not contains a benzene ring as part of its molecular structure.
What is a conjugated protein?
One that gets part of their function from a prosthetic group.
Claisen Condensation reaction (beta-keto ester formation)
Only covering ethyl esters
Ortho/Meta/Para
Ortho- : o- : located at carbon 2. Meta0 : m- : located at carbon 3. Para- : p- : located at carbon 4.
KMnO₄
Oxidation
How can you get ketones or aldehydes?
Oxidation of primary or secondary alcohols. Or ozonolysis of alkenes.
Radicals Reacting with Each Other
O₂ with X. forms a new radical, thus preventing X. from reacting with an organic substrate. *Radical inhibitor or radical scavengers are compounds that prevent radical reactions from occuring. ex. 02, Vit E.
Trans-
Parent chain continues on the opposite side of the double bond
Cis-
Parent chain continues on the same side of the double bond
5 Carbons
Pent-
18.9 Gasoline Summary
Petroleum consists mainly of hydrocarbons, which are then separated by molar mass in fractional distillation during the refining process.
19.4 Phenols Summary
Phenols are weak acids as a result of delocalization and stabilization of the conjugate base.
Elastomers
Polymeric materials that return to their original shapes after stretching.
Polynucleotides
Polymeric species built from nucleotide units.
Radical Polymerization
Polymerization by a radical chain reaction.
Polyesters
Polymers formed by linking together monomers that have carboxylic acid groups with those that have alcohol groups.
Copolymers
Polymers made of more than one type of repeating unit.
Condensation Polymers
Polymers made via condensation reactions.
19.12 Physical Properties of Polymers Summary
Polymers melt over a high range of temperatures, and polymers consisting of long chains tend to have high viscosities. Polymer strength increases with increasing chain length and the extent of crystallization. Thermoplastic polymers are recyclable.
Polysaccharides
Polymers of glucose.
State and explain Zaitsev rule. what type of reactions does it apply to? what does it predict?
Predicts minor and major products in elimination reactions. Predicts location of double bond in product. Predicts which beta hydrogen is likely to leave. States that the beta Carbon with the least Hydrogens is more likey to lose its hydrogens (poor get poorer).
3 Carbons
Pro-
Polar Reactions
Process which involve asymmetrical (heterolytic/heterogenic) bond-breaking or bond-making Much more common in organic reactions
Radical Reactions
Processes which involve symmetrical (homolytic/homogenic) bond-breaking or bond-making
19.13 Proteins Summary
Proteins are polymers made of amino acid units. The primary structure of a polypeptide is the sequence of amino acid residues; secondary structure is the formation of helices and sheets; tertiary structure is the folding into a compact unit; quaternary structure is the packing of individual protein units together.
How can one make an anhydride?
React a carboxylic acid with a carboxylate salt or heat! to stabilize the carboxylic acid.
Substitutions reaction
Reaction when a group of atoms, replaces another atom or group of atoms
Radical Halogenation
Reactions occur with racemixation at a stereogenic center. From the front and back.
Radical
Reactive intermediate with a single unpaired electron, formed by homolysis (breaking into same parts) of a covalent bond.
H₂, Pt/2000 psi
Reduction of Ring and Substituent to Single Bonds
H₂/Pd
Reduction of Substituent to Single Bonds
Zn(Hg), HCl or NH₂ NH₂ + OH-
Reduction to Alkyl
Pd/H₂ or Fe/HCL or Sn/ HCL
Reduction to Aniline
Fractional distillation
Repeated distillations on inert objects like glass beads that help separate two liquids with boiling points less than 25 C apart.
Naming of carboxylic acids
Replace the -e of the parent hydrocarbon with -oic acid.
Why are carboxylic acids that much more acidic?
Resonance stabilization of between the alcoholic oxygen and the carbonyl oxygen.
2 R-Li, CuI, ether
Results from ______ + ______. Reaction occurs in ______.
R₂CuLi, R'-X, ether
Results from ______ + ______. Reaction occurs in ______.
R-X, 2 Li, Pentane
Results from ______. Reaction occurs with ____ over ____.
R-X, Mg, ether
Results from ______. Reaction occurs with ____ over ____.
R-Mg-X, H₃O⁺
Results from ______. Reaction occurs with ____.
R-R', RCu, LiX
Results in ______ + ______ + ______.
R-H, HOMgX
Results in ______ + ______.
R-Li, LiX
Results in ______ + ______.
[R-Cu-R]⁻ Li⁺, LiI
Results in ______ + ______.
R-Mg-X
Results in ______.
R-Mg-X
Results in _______.
How do you get an acyl halide from a carboxylic acid?
SOCl₂
Isomers
Same formula, different structure
18.1 Types of Aliphatic Hydrocarbons Summary
Saturated hydrocarbons have only single bonds; unsaturated hydrocarbons have one or more multiple bonds. Alkanes are saturated hydrocarbons. Alkenes and alkynes are unsaturated hydrocarbons; the former have carbon-carbon double bonds and the latter have triple bonds.
Alkanes
Saturated hydrocarbons. In an alkane, the bonds lie in a tetrahedral arrangement with sp³ hybridization. They are the most "flexible" hydrocarbons.
What level of structure is guided by hydrogen bonds for proteins?
Secondary structure resulting in α-helix and β-pleated sheets.
Thin-Layer Chromatography
Silica gel is polar!!
Functional Groups
Small groups of atoms that lend characteristic properties to molecules they are attached to.
With respect to optical activity, what do your end products of Sn1 and Sn2 reactions become?
Sn1 = racemic mixture (nucleophile can attack from either the top or the bottom of the planar carbocation), therefore loss of optical activity. Sn2 = inversion of configuration and remains optically active.
Ring Opening of Epoxides - Base catalyzed
Sn2 like mechanism
Preparation of Nitriles|(Replace Halide with cyano)
Sn2 mechanism - preferably 1°
true
Solvation of any species decreases the entropy of the solvent because the solvent molecules become much more ordered as they surround molecules of the solute
true
Solvation of any species decreases the entropy of the solvent because the solvent molecules become much more ordered as they surround molecules of the solute.
Starch composition
Starch is made of two components: 20-25% amylose, and amylopectin.
Optical Isomers
Stereoisomers that are each others' nonsuperimposable mirror images.
Alkane
Straight chain hydrocarbons with all single bonds. (CnH₂n+₂)
18.2 Isomers Summary
Structural isomers have identical molecular formulas, but their atoms are linked to different neighbors. Geometrical isomers have the same molecular and structural formulas but different arrangements in space. Molecules with four different groups attached ti a single carbon are chiral; they are optical isomers.
nitration
Substitution of a nitro group (-NO2) for one of the ring H. The reaction occurs when benzene reacts with nitric accid in the presence of sulfuric acid as catalyst
Naming alkynes
Suffix -yne Prefixed by a number corresponding to the second carbon bonded in the chain, etc.
SO₃/H₂SO₄
Sulfonation
Homolytic Cleavage
Symmetrical distribution of electrons after bond breaking.
Acid anhydride Preparation
Symmetrical, unsymmetrical and 5 or 6 membered rings
Catalytic hydrogenation
Syn addition occurs
Epoxidation with a peroxyacid
Syn addition occurs
Hydroxylation with OsO4
Syn addition occurs
what the difference between syn and anti addition?
Syn is when both are added to the same side.. anti is both are added from opposite sides. resuts in gauche or staggered or anti alkane.
The weaker the C-H Bond, teh more readily the hydrogen atom is removed in radical halogenation
Tertiary carbons have less C-H bond strength (Lower Delta H and more stable radical) and as a result the ease of H abstraction is higher.
What level of structure determines whether you have collagen or myoglobin?
Tertiary structure in that at this level you have the determination of fibrous vs globular proteins.
What happens in a Benedict's test?
Testing for the presence of a reducing sugar. Aldoses and ketose can be oxidized to carboxylic acids and therefore producing Cu₂O (red) from benedict's reagent (started with Cu(OH)₂
What happens in a Tollens' Test?
Testing for the presence of a reducing sugar. Aldoses and ketose can be oxidized to carboxylic acids and therefore reduce Ag+ in the Tollens' test to metallic silver (Ag+ to Ag)
Peptide Bond
The -CO-NH- link found in a peptide.
Dispersal
The act or process of spread out or the condition of being disperse
Mechanism of amide formation
The amine could act as a base and simply accept a proton from the carboxylic acid; however, upon heating, a thermodynamically more favorable reaction takes place, the proton transfer is reversed and the amine acts as a nucleophile as it attacks the carbon of the carboxyl group.
Essential Amino Acids
The amino acids that the human body cannot produce and thus must obtain by via consumption.
free-energy change
The amount of free energy released (negative DG) or absorbed (positive DG) in a reaction at constant temperature and pressure.
Connectivity
The bonding orientation of atoms, etc. and such.
What looses an H first in basic titration, the amino or carboxyl group?
The carboxyl group duh!
protonated alcohol
The conjugate acid of the alcohol is often called a
alkyloxonium ion
The conjugate acid of the alcohol is often called a protonated alcohol, although more formally it is called an
oxonium ion.
The conjugate acid of the alcohol is often called a protonated alcohol, although more formally it is called an alkyloxonium ion or simply an
stable
The delocalised pi electrons in an aromatic compound mean it is very...
18.5 Properties of Alkenes Summary
The double bonds in alkenes can be generated by elimination reactions.
In gas chromatography what is the eluant and what is the stationary phase?
The eluant or mobile phase is a gas (He or N) and the stationary phase is the temperature-regulated column. Retention time: How long it took for each compound to travel through the column.
equilibrium constant
The equilibrium constant is Keq. It gives you information about the equilibrium concentrations of reactants and products.
19.2 Alcohols Summary
The formulas of alcohols are derived from that of water by replacing one of the hydrogen atoms with an organic group. Like water, they form intermolecular hydrogen bonds.
Oxidation
The gain of oxygen and/or the loss of hydrogen
notes
The general principle to apply is this: Acid-base reactions always favor the formation of the weaker acid and the weaker base.
of the weaker acid and the weaker base.
The general principle to apply is this: Acid-base reactions always favor the formation WHAT COMBONATION
What is a wittig reaction and what is its goal?
The goal is to make CARBON-CARBON double bonds by converting aldehydes and ketones into alkenes.
Polarization
The greater the difference in electronegativity, the greater is the
False; The larger the value of the pKa, the weaker is the acid.
The larger the value of the pKa, the stronger is the acid.
True
The less effective the orbital overlap, the weaker is the bond, and the stronger is the acid
18.6 Electrophilic Addition Summary
The mechanism of addition to alkenes is electrophilic attack.
Electrophilic Substitution
The mechanism of substitution on an electron-rich benzene ring; the electrophilic attack on an atom and replacement of one atom by another or by a group of atoms.
Radical Polymerization
The mechanism resembles the radical addition of HBR to an alkene, except that a carbon radical ranter than abromine atom is added to the double bond. 1. Initiation- A carbon radical is formed by a two step-progress 2. Propagation: The polymer adds chain growth. The more substituted radical adds to the less substituted end of the double bond. 3. Termination: Two radicals combine to form a bond.
α-Helix
The most common secondary structure in animal proteins; a helical conformation of a polypeptide chain held in place by H-bonds between residues.
electrophilic aromatic substitution
The most important reaction of aromatic rings
Phenyl
The name given to a benzene ring that is named as a substituent
The conversion of a carboxylic acid into ANYTHING depends on what?
The nucleophile!!
regiochemistry
The orientation of a reaction taking place on an unsymmetrical substrate. positional isomers
Enantiomers
The pairing of a chiral molecule and its mirror image.
Esterification
The process of creating esters, ex. the heating of acetic acid and ethanol to produce ethyl acetate and water.
Why is temperature important in recrystallization?
The product needs to be soluble in high temps and insoluble in lower temperatures. IMPURITIES need to be soluble at all temperatures so that they stay in solution.
Ester
The product of a reaction between a carboxylic acid and an alcohol.
Amide
The product of an amine condensing with a carboxylic acid.
powerful
The property the electrophile must have to participate in electrophilic aromatic substitution
Allylic Halogenation
The reaction follows a radical chain mechanism.
β-Sheet
The second most common secondary structure found in animal proteins; consisting of pleated sheets.
Primary Structure of a Protein
The sequence of residues in a peptide chain.
Secondary Structure of a Protein
The shape adopted by the polypeptide chain; in particular, how it forms coils or sheets.
Tertiary Structure of a Protein
The shape into which a protein's secondary structure is folded into as a result of interactions between residues.
benzene
The simplest aromatic compound
Why substitution but not addition occurs on benzene rings
The stability from the delocalized π-electrons is not makes the ring reluctant to allow an addition as that would destabilize the ring.
18.3 Properties of Alkanes Summary
The strength of the London forces between alkane molecules increases as the molar mass of the molecules increases; hydrocarbons with unbranched chains pack together more closely than their branched isomers and so it takes more energy to separate their molecules. Alkanes are not very reactive, but they do undergo oxidation (combustion) and substitution reactions.
conjugate base
The stronger the acid, the weaker will be its
Cellulose
The structural material of plants, held together by hydrogen bonds.
Repeating Unit
The structure that repeats over and over to produce a polymer chain.
Monohalogenation
The substitution of a single H by X can be achieved experimentally by adding X2 to an excess of alkane.
cyclic, delocalised pi electrons
The two defining features of an aromatic compound
Why is rotation of the peptide bond limited?
There is resonance about the C-N bond giving it some double bond character.
What is a zwitterion and how does an amino acid look as such?
They are dipolar ions where each half neutralizes the other.
Reactivity of Ethers
They are not very reactive and have low molecular polarity, making them useful solvents for other organic compounds. However, they are flammable.
What is significant about the α hydrogens on a β-dicarboxylic acid?
They are very acidic due to stabalization!
Properties of Crown Ethers
They bind very strongly to some metal cations, ex. encasing a K⁺, with the Os pointing towards the K⁺ and the hydrocarbons wrapped around the outside. This lets you mix polar solutes into nonpolar solvent.
Amino acids are amphoteric. Why?
They can act as an acid or a base. They have at least two dissociation constants (from H's on the n and c terminus)
There are four possible forms of an amino acid
They differ in the extend of protonation of the two functional groups, i.e. changed/changed, changed/unchanged, u/c, u/u.
What are anomers?
They differ only in the newly formed chiral carbon (after ring formation). Can be α vs β. Glucose the α anomer is trans and the β anomer is cis (both pointing up!)
Nucleophilic Addition of Phosphorus ylides to Aldehydes/Ketones: The Wittig Reaction
Through Betaine Intermediate
Hydroxylation of Alkenes
Through Osmate intermediate: anti addition|Through Epoxide intermediate: syn addition
Acid halide Reduction
Through aldehyde intermediate
Conjugate Nucleophilic Addition to alpha,beta-Unsaturated Aldehydes and Ketones
Through resonance stabilized enolate ion
define Halohydrin formation. what is added? what are reacants.
Treatment of an alkene with X₂and water add chlorine or bromine and OH
Whenever two different resonance structures can be drawn for an allylic radical, two different allylic halides are formed
True
True
True or False.....Questions Many of the reactions that occur in organic chemistry are either acid-base reactions themselves or they involve an acid-base reaction at some stage
Only primary alcohols can be oxidized to carboxylic acids. T/F?
True!
Naturally-occuring amino acids are L-enantiomers. T/F? Fischer projection?
True!! Fischer projections of amino acids have amino group to the left!
A low concentration of Br2 favors allylic substitution over addition. If concentrations of both intermediates-bromonium ion and Br- are low, the overall rate of addition is very slow.
True.
The stability of a radical increases as the number of alkyl groups bonded to the radical carbon increases.
True. Ch3<RCH2,R2CH<R3 C Increasing alkyl substitution increases radical stability. More stability equals lower bond dissociation energy of the C-H bond.
In radical addition (Hbr with added light, heat or ROOR, Br- adds first to generate the more stable radical and in ionic addition H+ adds first to genreate the more stable carbocation.
True. HBR adds to alkenes under radical conditions, but HCL and HI do not.
Transition states in endothermic rx resemenble the products. The more stable product is formed faster. T or F
True. In exothermic reactions the transition states resemble the starting materials. The relative stability of products does not greatly affect the relative energy of the transition states, so a mixture of products often results. *Because the rate-determing step in bromination is endothermic, the more stable radical is formed faster, and often a single radical halogenation product predominates.
Addition Reaction
Two molecules combine H2C=CH2 + H2 --> CH3CH3
Chlorination of Ethane
Two propagation steps results in two energy barriers. The first step is rate-determining because its transition state is at higher energy. Rate is exothermic.
Initiation
Two radicals are formed by homolysis of a sigma bond and this begins the reaction.
Termination
Two radicals combine to form a stable bond. Removing radicals from the reaction mixture without generating any new radicals stops the reaction.
9-BBN is used where?
Undergoes hydroboration in the same manner as BH₃ (general structure: R₂BH)
Addition Polymers
Unsaturated Compound →Radical Initiator→ Pi bonds break and C's string together to make long chain; chain grows until all monomers are used up.
when do we use the E / Z nomenclature?
Used when there are 4 different groups on an alkene (unable to assign cis/trans). - Assign priorities to the substituents on each end using rules for R/S - Assign E or Z based on location of higher priority groups (E = opposite sides; Z = same sides)
Ester Hydrolysis
Using Base is called Saponification
Can nitrogen-containing compounds be optically active?
Usually not because of nitrogen inversion but sometimes they can be isolated if the structure hinders inversion.
Polymers
Very long chains of repeating units (monomers) (Simplest polymer: -(-CH₂CH₂CH₂CH₂CH₂-)- =Polyethylene)
Hygroscopic
Water-absorbing
Carboxylic Acids
Weak acids of the form R-COOH.
Residue
What each monomer used to form a peptide is called.
Denaturation
When a protein loses its structure; contrary to the MCB definition, the Chem 204 version also includes the cleavage of primary structure sequences.
Markovnikov's Rule
When adding to an alkene, put the H on the C with the most H's already. ("The rich get richer")
What is a cyanohydrin?
When al and ke react with HCN.
How do you get an acetal or ketal?
When an aldehyde or ketone reacts with two equivalents of alcohol. A hemiketal or hemiacetal you get from one equivalent of alcohol.
When might decarboxylation occur?
When carboxylic acids are heated, they may spontaneously loose a CO₂
Stereoregular
When each unit or repeating unit has the same relative orientation.
What is zaitsev's rule?
When producing alkenes (usually from elimination reactions) there will be a major and minor product, the major one being the more subsituted and stable form.
When would distillation be favored over a separatory funnel?
When two liquids are miscible, the separatory funnel cannot be used therefore distillation is more ideal.
What is a wash?
When you are using the extraction to remove impurities rather than separate out the desired product.
Acid halide Alcoholysis - Acylation of alcohols
Will react preferentially with 1°>2°>3° OH
True
With hybrid orbitals, having more s character means that the electrons of the anion will, on the average, be lower in energy, and the anion will be more stable
...
With hybrid orbitals, having more s character means that the electrons of the anion will, on the average, be lower in energy, and the anion will be more stable.
Electron withdrawing vs donating...what do each do to a negative charge and acidity?
Withdrawing delocalize/stabillize the negative charge (spread it over the molecule) which increase acidity. Donating do the opposite.
Acidic cleavage of ethers
X = Br, I
OH, HX, ether
X replaces __. Reaction occurs with ____ over ____.
Reactions Involving Sulfer|Thiol - Sulfone
Y = Cl, Br, I, Tos
Can nitrogen containing compounds form hydrogen bonds?
Yes, but the are not as strong as the hydrogen bond between H and oxygen! (Therefore lower boiling point).
What are the best conditions for an Sn2 reaction?
You must have a strong nucleophile for the backside attack (thats what she said) with no steric hindrance.
acidity of phenols
[Section 21.4B] - weak acids (pKa≈ 10)
Hydrogenolysis of benzyl ethers
[Section 21.4C] - catalytic hydrogenation - benzyllic esters cleaved
Reaction of Phenols with strong bases
[Section 21.4C] - react with strong bases to form water soluble salts
Kolbe synthesis: carboxylation fo phenols
[Section 21.4E] - Nu addition - reactants: phenoxide ion + CO₂ - products: substituted cyclohexadione --(keto/enol)--> aromatic ring
Oxidation of Phenols to Quinones
[Section 21.4F] - oxidation - reactants: phenol + H₂CrO₄ - product: 1,2-quinones or 1,4 quinones
Oxidation at a Benzylic position
[Section 21.5A] - oxidation with H₂CrO₄ - benzyllic carbon w/ at least 1 H is oxidized to carboxyllic group
Halogenation at a Benzylic position
[Section 21.5B] - halogenation; can use NBS - regioselective: benzyllic position favored; Br more regioselective than Cl - mechanism: radical chain mechanism (1) X₂ --> X∗ radical (2) X∗ radical abstracts benzyllic radical (3) reacts with X₂ to give halogenated product
Electrophilic Aromatic Substitution: Bromination / Chloronation
_5.jpg
toluene
a benzene ring w/ a methyl group
simmons smith
a carbenoid reacts with a alkene to form a cyclopropane
polymerization
a chemical reaction in which monomers are binded together
mercaptans
a common name for any molecule containing an -SH group
aryl group
a group derived from an arene by removal of an H atom from an arene and given the symbol Ar-
steric effects
a group influences another group by filling space
polynuclear aromatic hydrocarbon
a hydrocarbon containing two or more benzene rings, each of which shares two carbon atoms with another benzene ring
Entropy
a measure of the disorder of a system
pyridine
a ring with a non carbon atom
monomer
a simple compound whose molecules can join together to form polymers
Hydrogen Bonding
acceptor must have: 1. lone pair 2. anion or small (O,N) neutral atom
Whats another word for ethyne?
acetylene
50
acid strength of alkanes
44
acid strength of alkenes
Synthesis: How do you form an alkyl halide?
add H and X to an alkane or add them twice to a alkyne. called Hydro-halogenation
describe the electrophilic acid catalyzed Hydration mechanism.
addition reaction. (not sure if this pic matches) THREE steps: (protonation of H₂O occurs prior to actual mechanism) 1. pi bond attacks hydrogen of hydronium. snatching it, and forming a new C-H bond. an intermediate Carbocation is formed. 2. water Nucleophilic attacks carbocation, forming new C-O bond 3. water now as base de-pronates the water added in the prevous step, leaving the OH. the acid can go on to do it again.
define Hydroboration-Oxidation. what is added?
adds water slash converts an alkene to an alcohol. actually 2 reactions: a hydro boration then an peroxide oxidation.
44
akenes pka is
15-18
alcohol pka is
50
alkanes pka is
25
alkynes pka is
38
amines pka is
acidity constant
an equilibrium constant for the ionization of an acid in water *KA= conj. base H3O+ weak acid *K H2O= A- H3O+ HA
zwitter ion
an ion with both + and - charges in same ion
Deuterium
an isotope of hydrogen which has one neutron (as opposed to zero neutrons in hydrogen)
deuterium
an isotope of hydrogen which has one neutron (as opposed to zero neutrons in hydrogen)
explain Hydroboration: regioselectivity
aniti anti anti anti ANTI-Markovnikov! With unsymmetrical alkanes, the Boron atom bonds to the LESS substituted carbon atom (and therefore, the OH group also bonds to the less substituted carbon).
diol
any of a class of alcohols having 2 hydroxyl groups in each molecule
explain Markovnikov's Rule. when does it apply?
applies to addition reactions to unsymmetrical alkene. predicts where things get added. predicts that the hydrogen bonds to the less substituted Carbon, and x bonds to more substitued Carbon. considered with hydrohalogenation and hydration
Kahn Ingold Prelog rules
are a set of rules used in organic chemistry to name the stereoisomers of a molecule. assign an R or S descriptor to each stereocenter and an E or Z descriptor to each double bond
inductive effect
are electronic effects transmitted through bonds
Inductive effects
are electronic effects transmitted through bonds. The inductive effect of a group can be electron donating or electron withdrawing. Inductive effects weaken as the distance from the group increases
Electrophiles
are reagents that seek electrons so as to achieve a stable shell of electrons like that of a noble gas.
lewis base acid definition
broader definition of acids 5s +
true
can you resonance structures can be drawn for either ethanol or ethoxide anion.
geminal carbon
carbon attached to same parent carbon
4-5
carboxylic acid pka is
Heterolysis
chemical bond cleavage of a neutral molecule generating an anion and cation. The anion receives both electrons.
electrophilic aromatic substitution
chemistry of benzene rings
aromatic sextet
closed loop of electrons (two from the second bond of each double bond) characteristic of a benzene ring
Exaplin E and Z affects in physical propertes of alkenes.
compared to trans, Cis or Z have higher melting point and boioiling point, due to partially re-enforcing dipole moments.
wurtz reaction
coupling of C atoms to make alkane (couple free radicals)
Lewis acid
electron pair acceptor
in contrast to alkanes, what type of compound does alkene especially react with?
electrophile.
explain the Hydroboration-oxidation mechanism
first, in one step called Hydroboration, the pi attacks the BH3, resulting in syn addition of 1 Hydrogen and 1 BH3. next, oxidation substitutes the BH2 with a OH. no intermediate carbo cat ion is formed;
hoffman product
formed by reaction with a big bulky base. Potassium T Butoxide
zaietz's rule
formed by reaction with a small base. Sodium Matn Oxide.
capsaicin
found in chili peppers, contains phenol and phenol ether.
initiator
free radical that starts polymerization
alcohols
functional group, OH bonded to tetrahedral carbon atom
exocyclic
hoffman product
35
hydrogen pka is
in terms of regio selectivity, What goes to the least substituted carbon in each of the 4 addition reactions.
in Halo-hydro formation, X goes goes to least substituted. in Hydro- halogenation and electrophilic hydration, H goes to least. In hydro boration, OH goes to least.
markovnikov's rule
in addition of H-X to an alkene, the hydrogen becomes attached to the carbon atom that is already bonded to more hydrogens
In which mechanism/s is carbon rearrangement (1,2 methyl or 1,2 H shifts) possible?
in the reactions with carbo- cation intermediates. - SN1 and E1 plus the following easy addition reactions: - Hydro-halogenation - Hydration
nucleophile
is a Lewis base that seeks a positive center such as a positively charged carbon atom.
acid strength
is characterized in terms of acidity constant (Ka) or pKa values
hydroxide ions
is the strongest base that can exist in water to any significant extent: Any base stronger than hydroxide will remove a proton from water to form hydroxide ions
What is jones reagent and what does it do?
it is CrO₃, H₂SO₄ in acetone and it oxidizes primary alcohols to carboxylic acids (STRONG!)
describe the Halohydrin formation mechanism
look for weird 3-way first step. 1. the pi attacks one of the halogens, who dumps his electrons to the other halogen and forms a bridged halonium + ion. 2. now the water nucliophilic attacks the most substituted carbon. 3. then another water, as a base stips off a hydrogen (see RIGHT product in image)
explain the Halogenation mechanism.
look for weird 3-way first step. 1. the pi attacks one of the halogens, who dumps his electrons to the other halogen and forms a bridged halonium + ion. 2. the mad dumped halogen ion now nucliophilic backside attacks one of the carbons forming a vic di halide. (see left product in image)
Bromination
mechanism
Chlorination
mechanism
Friedel-Crafts Alkylation
mechanism
Nitration
mechanism
Sulfonation
mechanism
Is there a way to convert primary and secondary alkyl halides into carboxylic acids? Sure!!
nitrile formation followed by acid or base catalyzed hydrolysis.
thiols
organic compounds containing sulfhydryls (-SH) group bonded to a tetrahedral carbon
True
pKa is directly proportional to the ph and inversely proportional to the ka
For addition reactions, what bond is broken and what bonds are formed.
pi bond of an alkene broken; two new sigma bonds are formed.
kinetic control
product are determined by the relative rates of formation
thermodynamic control
products are determined by the relative stability of each
G. N. Lewis
proposed a theory that significantly broadened the understanding of acids and bases.
Brønsted-Lowry Bases
proton acceptor
Brønsted-Lowry Acids
proton donor
inductive effect
pull of e- density through sigma bonds caused by electronegativity differences of atoms
Lindlar reaction
reduces triple bonds to double bonds using a heterogenous catalyst. This stops a reaction
electrostatic potential
shows attraction or repulsions between molecules
will this app allow curse words
sofa king good.
protic solvent
solvents with protons in solution, e.g. water or alcohol. large atoms tend to be better nucleophiles in here because they can shed the solvating protons around them and are more polarizable
carbene
sp2 hybridized carbon atom, has a lone pair
Alkene
stability controlled by: 1. internal vs. terminal 2. conjugation 3. degree of substitution 4. strain
In the book, they make a big deal out of pointing out the exception in the halonium formation reaction. explain what to remember about this discussion
the OH bonds to the most substituted Carbon. THe halogen ends up on the least substituted carbon.
explain Halogenation stereochemistry
the backside attack of the last step forms a anti addition, racemic mixture because ...I dont' know
Delocalization
the concept in which bonding electrons are not confined to the region between two atoms, but may be spead over several atoms or a whole piece of metal
dehydration
the elimination of a molecule of water from an alcohol. OH is removed from one carbon and H is removed from the other
Enthalpy
the heat content of a system at constant pressure
hydrogen bonding
the intermolecular force in which a hydrogen atom that is bonded to a highly electronegative atom is attracted to an unshared pair of electrons of an electronegative atom in a nearby molecule
equilibrium constant
the ratio of product concentrations to reactant concentrations at equilibrium, with each concentration raised to a power equal to the number of moles of that substance in the balanced chemical equation
explain Halohydrin - stereochemistry / regioselectivity
trickey exceptions here. Regioselectivity: electrophile bonds to less substituted C and -OH binds to MORE substituted C. Stereochemistry: anti addition occurs
rearrangement
type of reaction
Synthesis of Ethers - Method 1/3 Williamson Ether Synthesis
via Sn2 mechanism - inversion of configuration of R'-Y= Cl, Br, I, Tos
15.76
water pka is
homolysis; radicals
what forms after the bond break
heterolysis
what is it, the bond is always polarize
forward
whenever the base has a larger number in pka the reaction goes?
when do we consider methyl and H shifts?
whenever there are carbo cation intermediates. like in SN1, E1 and in Hydro-halogenation and electrophillic hydration
5
which has the greatest acidity
2
which one increase 1 or 2
endocyclic
zaietz's rule
Dehydration of Alcohols to yield Alkenes - Method 1/2 - Acid Catalyzed
|-E1 mechanism|-Multiple Products (Zaitsev's Rule)
Dehydration of Alcohols to yield Alkenes - Method 2/2 - Using Phosphorus oxychloride
|-E2 mechanism|-Ester intermediate = R-O-PCl2
Preparation of Epoxides
•A two step-reaction sequence: [1] Removal of a proton with base forms an alkoxide [2] Intramolecular SN2 reaction forms the epoxide.
Reaction with HX to form RX
•Order of reactivity: R3COH > R2CHOH > RCH2OH. •The mechanism for 2o and 3o ROH is SN1; carbocations are intermediates and rearrangements occur. •The mechanism for CH3OH and 1o ROH is SN2.
Dehydration of an Alcohol (Strong Acid)
•Order of reactivity: R3COH > R2CHOH > RCH2OH. •The mechanism for 2o and 3o ROH is E1; carbocations are intermediates and rearrangements occur. •The mechanism for 1o ROH is E2. •The Zaitsev rule is followed.
Reaction with other Reagents to form RX
•Reactions occur with CH3OH and 1o and 2o ROH. •The reactions follow an SN2 mechanism.
Reactions of Alkyl Tosylates
•Substitution is carried out with strong :Nu- so the mechanism is SN2. •Elimination is carried out with strong bases so the mechanism is E2.
Reaction with Tosyl Chloride
•The C-O bond is not broken so the configuration at a stereogenic center is retained.
Dehydration of an Alcohol
•The mechanism is E2. •No carbocation rearrangements occur.
Preparation of Alcohols
•The mechanism is SN2. •The reaction works best for CH3X and 1 degree RX.
Preparation of Ethers
•The mechanism is SN2. •The reaction works best for CH3X and 1 degree RX.
Reactions of Epoxides
•The reaction occurs with backside attack, resulting in trans or anti products. •With :Nu-, the mechanism is SN2, and nucleophilic attack occurs at the less substituted C. •With HZ, the mechanism is between SN1 and SN2, and attack of Z- occurs at the more substituted C.
Reactions of Ethers
•With 2o and 3o R groups, the mechanism is SN1. •With 1o R groups the mechanism is SN2.