Ch 42-45 reactions and functional groups
epimer
*subtype of diatereomers *differ in configuration at exactly one chiral carbon
imine formation
- Ammonia (NH3) is added to the carbonyl, resulting in the elimination of water - can undergo tautomerization and form enamine - Example of condensation reaction since a small molecule is lost during the formation of a bond between two molecules.
Ether Synthesis
- condensation of two molecules of an alcohol -metal oxides with primary alkyl halides or tosylates - phenol and NaOH, H2O - oxirane
equatorial
- in the place of the molecule - largest substituent will generally take this position to reduce strain
SN1
-2 steps -Rate limiting step, so reaction rate is dependent on concentration of R-X tertiary substrate is best do not require strong base good leaving group required prefer protic solvent (acid) varied steriochem because nucleophile can attack from top or bottoms can produce racemic mixture
E1
-2 steps -Rate limiting step, so reaction rate is dependent on concentration of R-X tertiary substrate is best do not require strong base good leaving group required prefer protic solvent (acid) major product is the more substituted heat makes this more favorable over SN1
synthesis of anyhydrides
-acyl chloride reaction -cyclic anhydride self-condensation -condension of 2 cooh
ring flip
-atoms/groups that were equatorial become axial and vice versa
anhydrides
-carboxylic acid derivative -had water molecule removed during formation -formed from 2 carboxylic acid molecules -named by replacing acid with anhydride in the name of the carboxylic acid if anhydride is formed from only 1 type of carboxylic acid -if anhydride is not symmetrical, both carboxylic acids are named before the anhydride is added to the name (ex: ethanoic propanoic anhydride) -no hydrogen bond less poor and lower bp and melting points not soluble in water
Hofmann Rearrangement
-converts amides to primary amines with the loss of the carbonyl carbon as a molecule of CO2 formation of nitrene which rearranges to form isocyanate which is hydrolyzed into amine
carboxylic acid
-oic acid Always terminal most highly oxidized organic compound H of OH is highly acidic (3-6 pKA) can form hydrogen bonds high boiling point, which increases wth molecular weight adding EDG- decreases acidity adding EWG- increases acidity
ketone
-one location must be specified oxo- dipole moment -> elevation in bp but still lower than OH because no H bonding
Synthesis of Aldehydes and Ketones
-oxidation of alcohols -oxidative cleavage of alkenes - acetylation
acyl halide
-yl halide the most reactive of the derivatives carbonl always reforms No H bonding so slightly lower bp and mp
SN2
1 step concerted backside attack rate depended on both nucleophile and substrate reaction less substituted carbon is most reactive strong nucleophile strong leaving group prefer aprotic (acetone, DMSO) if chiral -> flip when Lg and nuc have same priority
E2
1 step concerted loss of H+ and LG rate dependent on both nucleophile and substrate strong base required good leaving group required often performed in conjugate acid of strong base used heat gives an advantage over SN2 trans>cis
alkene to ketone
1) KMnO4, OH-, heat 2) H+
alkene to aldehyde
1) O3 2) Zn, H20 (or CH3SCH3)
tosylate
A compound containing the functional group -SO3C6H4CH3, derived from toluenesulfonic acid used to convert alcohol into something else
racemic mixture
A mixture that contains equal amounts of the (+) and (-) enantiomers. are not optically active.
aldol condensation
A reaction in which an aldehyde or ketone acts as both the electrophile and nucleophile, resulting in the formation of a carbon-carbon bond in a new molecule called an aldol water becomes a good leaving group and the extra electrons left over becomes a double bond leto-target enol- nucleophone
electrophilic aromatic substitution
A reaction in which an electrophile is substituted for a hydrogen on an aromatic ring.
nucleophilic substitution
A type of substitution reaction in which a nucleophile is attracted to an electron-deficient centre or atom, where it donates a pair of electrons to form a new covalent bond. nucleophile attacks carbonyl and then OH becomes a good leaving group and the carbonyl reforms
electrophile
An electron pair acceptor loves electrons gets attacked by nucleus
nucleophile
An electron pair donor loves the nucleus attacks the electrophile
meta directors
CHO COOR COOH COCl CN SO3H NR3+ NO2
phosphate esters
Can form between a phosphate and a free hydroxyl group. Phosphate groups are often attached to proteins in this way.
Synthesis of Carboxylic Acids
Carboxylic acids can be prepared via oxidation of aldehydes and primary alcohols. The oxidant used for this is usually dichromate salt (Na2Cr2O7 & K2Cr2O7), chromium trioxide (CrO3) or potassium permanganate (KMnO4) can also use oxidative cleavage of alkenes, organometallic reagents, hydrolysis of nitrils
geometric isomers
Compounds that have the same molecular formula but differ in the spatial arrangements of their atoms. cis/trans e/z
wittig reaction
Converts a ketone (C=O) to and alkene (C=C). 1) A phosphorus ylide (a neutral molecule with a negatively charged carbanion) acts as the nucleophile toward the carbonyl C forming a betaine (beta-ine) with a P+ and an O-. 2) Betaine is unstable so cyclization quickly gives the alkene (C=C) and a triphenylphosphine oxide (P=O). When possible, a mixture of cis and trans isomers is formed.
ring strain
Energy created in a cyclic molecule by angle strain, torsional strain, and nonbonded strain; determines whether a ring is stable enough to stay intact.
acyl halide to aldehyde
H2 Pd/BaSO4
alkynes to alkenes
H2, Lindler's catalyst (cis) or Na, NH3 (trans
hydration of alkenes
H2C=CH2 + H2O -> CH3CH2OH alkenes + h2o with acid to form an alcohol
sulfonation of benzene
H2SO4 fuming
aldehyde and ketone reaction with HCN
HCN attacks the carbonyl etc
nitration of benzene
HNO3, H2SO4
Anti-Markovnikov Addition
In the presence of peroxides (ROOR), Bromine from HBr, not the hydrogen, will add to the least-substituted Carbon (does not apply with other halogens - those will still add Markovnikov).
torsional strain
Increased energy that results when molecules assume eclipsed or gauche staggered conformations more -> more energy ->. less stable
acyl group
It is a functional group of organic compounds which is usually obtained by replacing the hydroxyl group (--OH) from any carboxylic acid.
Aldehyde oxidation
KMnO4, CrO3, Ag2O or H2O2 makes carboxylic acid
ester reduction
LAH produces primary alcohol
aldehyde/ketone reduction
LAH or NaBH4
amide reduction
LiAlH4 is used to reduce this to a amine
LiAlH4
Lithium aluminum hydride is a very strong reducing agent. It will reduce aldehydes, ketones, esters, and carboxylic acids to alcohols, and amides and nitriles to amines. It will also open epoxides.
ortho/para directors
NH2 OH OR R Benzene H X (Br, Cl, I)
L sugar
OH on left
D sugar
OH on right
enantiomer
One of two compounds that are mirror images of each other and that differ in shape due to the presence of an asymmetric carbon. nonsuperimposible mirror images that cannot be rearranged to be the same
Cleavage of ethers
Only under vigorous conditions using HBr or HI; proceeds by either Sn1 or Sn2 mechanism produces two alkyl halides most substituted carbon- attacked by acid least substituted carbon- attacked by base
oxidation of alcohols
Primary alcohols can be oxidized using PCC and further oxidized to carboxylic acids using KMnO₄, Na₂Cr₂O₇, or CrO₃. Secondary alcohols can be oxidized to ketones using any of these oxidants.
PCC
Primary alcohols to aldehydes and secondary alcohols to ketones
alcohols
R-OH hydroxyl group suffix: -ol, high priority for naming attached to a aromatic ring: phenol form hydrogen bonds high boiling points -> increasing with increasing hydroxyl groups
Friedel-Crafts Acylation
RCOCl, AlCl3 product more reactive than reactnat
amide
RCONR2 peptide bonds that link amino acids into proteins ar these bonds -amide have the ability to form hydrogen bonds very high melting and boiling points good water solubility least reactive
ether
ROR two alkyl or aryl groups bonded to a single oxygen atom no hydrogen bonding boil at low temps only slightly polar only slightly soluble in water frequently used as solvents can form highly reactive peroxides
Friedel-Crafts Alkylation of Benzene
RX, AlCl3
reaction with weak base and aprotic solvent
SN2 (methyl, primary, secondary)
reaction in aprotic solvent
SN2 or E2
acyl halide formation
SOCl2
NaBH4
Sodium borohydride is a reagent for the reduction of ketones and aldehydes, it will also reduce acid halides. It is also used in the oxymercuration reaction to replace mercury with H. DOES NOT REDUCE COOH or ESters
decarboxylation
The complete loss of a carboxyl group as carbon dioxide
Zaitsev's Rule
The most substituted alkene is formed preferentially
steric hindrance
The prevention of a reaction at a particular location in a molecule by substituent groups around the reactive site.
z isomer
The same groups are on the same side of the double bond Cis isomer
SOCl2
Thionyl chloride is used for the formation of alkyl chlorides from alcohols and acid chlorides (acyl chlorides) from carboxylic acids.
Markovnikov's Rule
When adding to an alkene, put the H on the C with the most H's already. ("The rich get richer")
Halogenation of benzene
X2, FeX3
aldehyde/ketone to alkane
Zn(Hg), Hg (clemmensen ) or H2NNH2, Base and heat (wolff-kishner)
Clemmenson Reduction
Zn(Hg)/aqHCl ketone to alkane
carboxylic acid synthesis
[carboxylic acids] oxidation of primary alcohols with KMnO4, hydrolysis of nitriles, carbonation with girgnard
KMnO4
a very strong oxidizing agent. primary alcohols and aldehydes -> carboxylic acids, secondary alcohols -> ketones alkenes -> diols oxidatively cleave carbon-carbon multiple bonds.
hydrolysis of amide
acidic conditions allow carbonyl O to become protonated => Nu attack by water => carb acid and ammonia basic conditions - attack and form carboxylate
carboxylic acid derivatives
acyl halides, anhydride, ester, amide all have highly polarized c=o
Ester and Grignard reagent
add to the carbonyl or the ester -> ketone ketone reacts quickly to produce tertiary alcohol
addition reaction to create alcohol
addition of water to double bonds addition of organometallic compounds to carbonyl groups
synthesis of alcohol
addition, substitution, reduction, phenol
electron donating group (activators)
adds e- density NH2 OH OR R Benzene H
transesterification
alcohol acts as a nucleophile and displaces the alkoxy group
acyl halide to ester
alcohol attacks and cl leaves and bonds with hydrogen when the carbonyl is reformed
anhydride to ester and carboxylic acid
alcohol reaction -> 1 of each
PCC
alcohol to aldehyde
conc. H2SO4
alcohol to alkene
dichromate salt
alcohol to ketone
addition of H2O
alkene to alcohol
mCPBA
alkene to epoxide
acyl halide to amide
amine (ammonia) attacks and displaces the halide as it reforms the carbonyl primary and secondary amines can be used as the nucrlophile
aryl group
an aromatic carbon ring system from which one hydrogen atom has been removed
michael addition
an enolate attacks an alpha,beta-unsaturated carbonyl, creaing a bond
aprotic solvent
any solvent that cannot donate H+
protic solvent
any solvent that contains H+ that is easily displaced
phenol synthesis
arylsulonic acid with heat hydrolysis of diazonium salts
least substituted carbon
attacked by a base
most substituted carbon
attacked by an acid
phenyl
benzene as a substituent
radical propagation
can occur multiple times starts with 1 radical, ends with 2 different radical chain reaction
aldehyde
carbonyl and alkyl group and hydrogen -al must be terminal highest priority group in a molecule
acyl halide to anhydride
carboxylate salt attacks and the cl is leaves as leaving group when carbonyl reforms
highest priority to lowest priority functional groups
carboxylic acid, esters, amides, nitriles, aldehydes, ketones, alcohols, amines, ethers the more oxidized the higher priority
Condensation of two carboxylic acids
condense to form anhydride anhydrous conditions only
hydrolysis of acyl halide
conversion back into carboxylic acid form irritating odor
substitution reactions with alcohol
convert OH to water-> good leaving group
anhydride hydrolysis
converts an anhydride back into a carboxylic acid
anti addition of halogens
cyclic intermediate that prevents nucleophilic attack on same side
pKa decreases
decrease in acidity potentially due to an EDG
elimination reactions with alcohol
dehydrated in a strongly acidic solution -> alkenes more stable produce: the more substituted
esters
dehydration products of carboxylic acids and alcohols -oate no H bonding less polar low mp and bp solubility depends on leith of hydrocarbon chain smaller- more soluble longer- less soluble
conformational isomers
differ by rotation around a single sigma bond
Reactions of Alcohols
elimination substitution oxidation
claisen condensation
enolate ion of one ester acts as nucleophile attacking another ester
triaglycerol
esters of long chain carboxylic acids
peroxide formation
ethers react w/ oxygen => highly explosive peroxides
radical initiation
extreme conditions (uv light or heat) generates radicals starts with 0 and ends with 2
polar head
face outwards
hydration of alkynes
form a carbonyl
aldehyde hydration
form geminal diols water attacks carbonyl and gets deprotonated and the o- gets protonated
Carbonation of Organometallic Reagents
grignard used with co2 to for cooh adds one carbon to the chain
catalytic hydrogenation of alkenes and alkynes
h2/pt end in a single bond
meso compound
have an internal plane of symmetry so do not have enantiomers do not exhibit optical activity
chiral centers
have four different groups attached to the central carbon
Cyclic anhydride self-condensation
heating carboxylic acids creates a ring releases water
SN2 can be inhibited
high substituted substrates or bulky bases
pKa increase
increase in acidity potentially due to an EWG
Wolff-Kishner Reduction
ketone to hydrazine (NNH2) using H2NNH2 then use a base to remove the hydrazone
micelle
lipid molecules that arrange themselves in a spherical form in aqueous solutions
soap formation
long chain hydrocarbon cooh react with NaOH or KOH -> salts which are soluble in aqueous solutions
reaction with strong base and aprotic solvent
methyl- SN2 primary- SN2 >E2 secondary - E2 > SN2 tertiary - E2
condensation of carboxylic acids and alcohols
mixture wil condense into esters under anhydrous conditions
leaving group
molecular fragment that departs with a pair of electrons ex) weak base, conj base of a weak acid, halogen
PBr3
molecule that replaces OH with Br in an Sn2 style reaction
isomerism
molecules built from the same part
structural (constitutional) isomers
molecules with same molecular formula but different bonds between atoms can have many different physical and chemical properties
phenols
more acidic than aliphatic alcohols (resonance) readily form salts with inorganic bases (NaOH) intermolecular hydrogen bonds high mp and bp only slightly soluble in water EWG -> increases acidity EDG -> decreases acidity
hydrolysis of nitriles
nitrile + hcl + 2h20 ---> carboxylic acid + nh4cl
ester to amide
nitrogen base attacks the carbonyl
ketone oxidation
not possible unless extraordinarily Harsh condition
nucleophilic addition to a carbonyl
nucleophile attacks carbonyl and the o- is protonated
anhydride acylation
occurs readily with AlCl3 aryl ketone and a cooh
trans
opposite side
ether reactions
peroxide formation cleavage
bulky nucleophile
primary, secondary tertiary E2
anhydride to amide
produces an amide and a carboxylic acid cleaved by ammonia then reacts with ammonia to form ammonium carboxylate
ester formation (starting with COOH)
reaction with alcohol under acidic conditions acidic- pronate the O first forms water also
acyl halide reduction
reduced to acolho with LAH selectively reduced to aldehyde using H2 and Pd/BaSO4
reduction reaction to form alcohol
reduction of aldehydes, ketones, carboxylic acids, esters LiAlH4 - stronger, less specific (reduces cOOH and esters ) NaBH4- milder more selective (not COOH or esters, but aldehydes and ketones)
dibromination to synthesize alkynes from alkenes
repetitive E2
optical activity
rotation of the plane of polarized light
cis
same side of the carbon chain
reaction with protic solvent and weak base
secondary or tertiary SN1 and E1
keto-enol tautomerization
shift from a carbonyl to an alkene with an alcohol. It is a reaction at equilibrium; these structures are not resonance structures
substitution to create alcohol
sn1 and sn2
radical termination
starts with 2 and ends with 0
Diastereomers
stereoisomers that are not mirror images opposite at some but not all sterocenters
electron withdrawing groups
strongly electronegative and pull electron density away from rest of the molecule, and stabilize negative charge. X CHO COOR COOH COCl CN SO3H NR3+ NO2
E isomer
the isomer with the high-priority groups on opposite sides of the double bond
radical reaction
three steps: initiation, propagation, termination cl2 (less selective) and br2 (more selective) will generate useful radicals that will react with alkanes f2 too reactive and I2 too unreactive
acetal and ketal formation
two. eq. of alcohol => acetal or a ketal in aldehyde => H is characteristic one eq. of OH => hemiacetal or hemiketal contains one OH in base, rxn would stop here
reaction of carboxylic acid
use LAH to return to primary alcohol
AlCl3
used in the presence of an acyl halide to add that thing to the benzene
R
used to resemble a generalized alkyl group
sugar
usually end in -ose aldoses - aldehyde ketoses- ketone
I-
very good leaving group because of its size
H of alcohol
weakly acidic
acyl halide acylation
with AlCl3 can react an attack a benzene and be added to the ring
Acyl chloride to ester
with alcohol under anhydrous condition
Hydrolysis of esters
yields carboxylic acid and alcohols acid- proton first, then attack carbonyl basic- attack first
