Chapter 6 (Reactions of Alkenes)

three carbons

3 (tertiary) means that there are _________ ___________ connected to the central atom

resonance; weak base

H2SO4 (instead of HCl, HI, HBr, etc) is used as the acid in acid-catalyzed hydration because sulfate ion has _____________ and is a _________ _________, therefore it does not react/add in the reaction

electron sink

an atom that accepts a new bond or lone pair of electrons; is what an arrow points toward in an organic chem mechanism

bond; nucleophile; electrophile

4 General Electron Movements in Organic Reaction Mechanisms: 1. Make a new ____________; arrows come from electron rich "source" (____________) and point towards an electron deficient "sink" (____________)

break; hypervalent; stable

4 General Electron Movements in Organic Reaction Mechanisms: 2. _________ an existing bond; do this to avoid ___________ atoms and to create relatively __________ species (either intermediates or products)

proton; acid; base

4 General Electron Movements in Organic Reaction Mechanisms: 3. Add a __________; typical if no obvious nucleophile and electrophile and there is a lot of strong _________ or strong _________ present

remove; strong

4 General Electron Movements in Organic Reaction Mechanisms: 4. _________ a proton; typical if no obvious nucleophile and electrophile and there is a lot of __________ acid/base present

positive

BDE has to be ______________ because its energy put into the molecule

3; 2; 1

__________ carbocation is more stable and requires a lower activation energy for its formation than a ________ carbocation; and a ________ carbocation is in turn more stable/requires less energy than a ______ carbocation

carbocations

______________ are a species in which a carbon atom has only six electrons in its valence shell and bears a positive charge; are classified as primary, secondary and tertiary depending on how many carbons are bonded to carbon bearing positive charge

racemic; possibility

a ____________ mixture can be made if the products have more then one ________________ hence they have enantiomers that could form (both have 50/50 chance of forming

electron source

a bond or lone pair of electrons usually an area of relatively high electron density, that serves as the origin of a mechanism arrow; interacts with an electron sink in an organic mechanism

rearrangement

a change in connectivity of the atoms in a product compared with the connectivity of the same atoms in the starting material

glycol (aka vicinal diol)

a compound with hydroxyl (-OH) groups on adjacent carbons

reactive intermediate

a high-energy species, formed between two successive reaction steps, that lies in an an energy minimum between the two transition states

faster

a more stable carbocation (3>2>1) forms __________ than a less stable carbocation intermediate

addition reaction

a reaction in which two atoms or ions react with a double bond, forming a compound with the two new groups bonded to the carbons of the original bond

carbocation

a species in which a carbon atom has only six electrons in its valence shell and bears a positive charge

delocalized; stable

a tertiary intermediate (carbocation) is more stable because of the positive charge (+) is spread; electrons are _____________ and spread out, making it more ___________ due to the partial overlap of sigma bonding orbital with empty 2p orbital (hyper-conjugation)

trans diaxial; axial

addition of chlorine or bromine to cyclohexene and its derivatives gives a ________ _________ product because only _________ positions on adjacent atoms of a cyclohexane ring are anti (one up; one down aka one wedge, one dash) and coplanar

acid-catalyzed hydration

addition of water across a double bond in the presence of an acid; obeys mark's rule

most stable; atom; group

after forming a carbocation as an intermediate in a mechanism, make sure that the positive charge is on the __________ _________ carbon (tertiary>secondary>primary), if not see if an ________ or __________ (typically alkyl group or hydrogen) can be rearranged/shifted to form a more stable carbocation

chiral centers; enantiomers

after forming the product of electrophilic addition; look to see if any __________ _________ were created-- if so investigate if any stereoisomers (like ______________ with inverted SC) can be formed or if the compound is ___________ (same)

chiral centers; stereoisomers; enantiomers; meso

after predicting product of reaction or finding the product through the mechanism, look to see if there are _______ _________ in the products; if yes then draw all the possible _____________ of the molecule then examine if they are ____________ (form either) or ______________ (same molecule)

regioselectivity

an addition or substitution reaction in which one of two or more possible products is formed in preference to all others that might be formed; obeys marks rule or anti marks rule ex: H-Cl has H form to side with more H's

tertiary; 3

an intermediate will be more stable if it's positive charge is on a ______________ carbon meaning its bonded to ______ other carbons

alkyl; electron-deficient; positive

carbocation rearrangement usually occurs when an _________ group (single bonded carbons) or a hydrogen migrates, each with with its bonding electrons, from an adjacent atom to the ____________-____________ atom (to the atom bearing a __________ charge)

back; wedges

figure out stereochemistry, by seeing how intermediate is oriented (usually front) then attacking from the __________ aka displays __________ on structural image (happens if ions/atoms are very large like Br or Cl)

none; syn (same side); OH, OH

for a oxidation of alkenes to glycol (vicinal diol) reaction 1. OsO4 2.NaHSO3, H2O regioselectivity: _________________ stereoselectivity: ______________ product groups: ______________

mark's rule; anti; H,OH

for a oxymercuration-reduction reaction (addition of H and OH) 1. Hg(OAc)2, H2O2 2.NaBH4: regioselectivity: _________________ stereoselectivity: ______________ product groups: ______________

ozone (O3); negatively; positively; concerted; molozonide

for a ozonolysis (clevage of alkene to make aldehydes and /or ketones) 1. O3, 2. (CH3)2S: 1. when an alkene is treated with ___________ (which has resonance), the ___________ charged O (nucleophile) attacks DB and the DB (electrophile) attacks neutral O and bond between O and central _____________ charged O breaks (this is ______________ meaning it happens simultaneously) to form the ____________ intermediate

cleavage; aldehyde; ketone

for a ozonolysis (clevage of alkene to make aldehydes and /or ketones) 1. O3, 2. (CH3)2S: 2. the relocating VE in molozonide results in ____________ of one carbon-carbon and one oxygen-oxygen bond; the two products are a ___________ or/and a ____________

CH2Cl2 (dichloromethane)

for addition of bromine and chlorine to an alkene, ____________ is usually used an an inert solvent to carry out these reaction

obeys mark's rule; none (scrambled); X,H

for addition of hydrogen halide, HX (X=Cl, Br, I) reaction: regioselectivity: _________________ stereoselectivity: ____________ product groups: __________

obeys Mark's Rule; scrambled; OH; H

for an addition of water, acid-catalyzed hydration: H2O/H2SO4 regioselectivity: ________________ stereoselectivity: _____________ produces product groups of _________ and ________

OsO4; resonance; osmate ester; syn

for an oxidation of alkenes to glycol (1.OsO4 2.NaHSO3, H2O): 1. an O atom from __________ (which expresses _____________ making it highly electrophilic because positive charge is delocalized) attacks DB while the DB attacks another O atom from OsO4 (concerted) which forms an _________ ___________ (or cyclic) intermediate attached in a _______ stereoselectivity

NaHSO3; broken; OH; syn

for an oxidation of alkenes to glycol (1.OsO4 2.NaHSO3, H2O): 2. ____________ is added to osmate ester intermediate and the bonds between O-Os attached to both carbons on either side is __________ (forming cis glycol) takes its place on each side the stereoselectivity of the product is _________ (both dashes, both wedges)- if product has chiral centers then look to see if form enantiomers or its meso

wedges; dashes

for chair conformations, ___________ on a group means up and __________ on a group means down `

down

for chair conformations, if you have an axial up, then equatorial must be ____________

planar hexagon representation

for cylcloalkenes, in order to visualize the attack of the Br or Cl ion to the intermediate formed from halogenation, you should draw the ____________ ____________ ______________ of the cyclo molecule

anti-marks; syn; H and OH

for hydroboration-oxidation (addition of H and OH), 1.BH3 2.H2O2, NaOH: regioselectivity: _________________ stereoselectivity: ______________ product groups: ______________

oxidation; reduction

for oxidation/reduction reactions of alkenes: __________= adding O to C; removing H from C __________= subtracting O from C; removing H to C

oxygen; DB; zig zag

for ozonolysis (clevage of alkene to make aldehydes and/or ketones): the double-bonded __________ (that makes up ketone/aldehyde products) is added/formed where original __________ split; *it helps when drawing products to number carbon chains and rotate images so molecule appear as _________ ________ carbon chains with attached double bonded O and other sub.*

none; anti; coplanar; OH H

for the addition of halogens reaction (Br2 and Cl2): regioselectivity: _________________ stereoselectivity: ______________ (and _________ for cyclohexenes bc creates trans diaxial) product groups: ______________

nucleophile; electrophile; breaking

for the electrophilic addition of a HX (hydrogen halides): 1. make a new bond between a _____________ (pi/DB) and an _____________ (add a proton- will be H); while simaltaneously _________ the bond between the H-X to result in formation of an organic cation and halogen ion

nucleophile; electrophile; ion; positively

for the electrophilic addition of a HX (hydrogen halides): 2. make a new bond between a ____________ and a ___________ (negatively charged ________ will form bond with ___________ charged atom on cation to form final product

mark's rule; anti; X,OH; X; H2O

for the halohydrin formation reaction (addition of HOCl or HOBr), H2O and Br2 or Cl2: regioselectivity: _________________ stereoselectivity: ______________ product groups: ______________ _________ attacks first to produce halonium ion then ________ attacks twice to form OH

one long chain; double bonded

for the ozonolysis (addition of O3, (CH3)2S) to cyclohexenes, the ring splits into _______ __________ ________ with two _________ __________ O on either side

carbocation rearrangement; 1,2 hydride; 1,2 methyl

if a more stable carbocation can form, then it will form through _____________ ____________ via a ______________ or _____________ shift

different; wedge; dash

if a reaction has a anti stereochemistry then the substitutes are added on ____________ planes of the molecule, hence they will have one __________ and one ___________ orientation

same; wedges; dashes

if a reaction has a syn stereochemistry then the substitutes are added on the __________ plane of the molecule, hence they will both have the orientation of __________ or __________

syn

if a reaction has the stereoselectivity of _________ then the two groups must be added across the same side of the double bond (only get one set of enantiomers)

anti

if a reaction has the stereoselectivity of ___________ then the two groups must be added across opposite sides of the double bond (only get one set of enantiomers)

hydrogen

if carbocation's positive charge is not on the most stable carbon and shifting a methyl would make the more stable option go away, shift a _____________ instead

meso; one

if the product formed has a chiral center but ends up being __________, only draw _________ conformation not both

first step

in a catalyzed reaction, the catalysis will most likely do ___________ __________ (acid in acid-catalyzed reaction will add first)

HgOAc+; DB; rearrangement

in a oxymercuration-reduction reaction (1. Hg(OAc)2, H2O2 2.NaBH4): first ___________ (electrophile) forms a brided mercurinium ion intermediate after ________ attacks it (intermediate occurs without ____________ bc it is a resonance hybrid but has character of bridged mercurinium ion)

H; anti

in a oxymercuration-reduction reaction (1. Hg(OAc)2, H2O2 2.NaBH4): lastly, C-HgOAc is reduced to a C-_____ bond after the addition of NaBH4 in flask; the final stereoselectivity is _________ so enantiomers may form (one dash, one wedge) if there are chiral centers

H2O; more; OH

in a oxymercuration-reduction reaction (1. Hg(OAc)2, H2O2 2.NaBH4): second ____________ anti attacks the __________ substituted carbon to open the three-membered ring of intermediate mercurinium ion then a second H2O removes H from O+-H to create the group __________

acid; hydronium; water

in acid catalyzed hydration, react the initial reactant with the ___________(___________ ion) first then react with _________ (twice to form C-OH bond then again to remove O-H bond)

mark's rule; none (scrambled); OH, H

in addition of water, acid catalyzed hydration (H2O; H2SO4 (H3O+)): regioselectivity: _________________ stereoselectivity: ______________ product groups: ______________

acid; hydronium

in an acid catalyzed hydration, the _________ (the __________ ion) is a product of the reaction since it acts as a catalysis (never disappears)

boron; less; concerted

in hydroboration-oxidation reaction (1. BH3, 2.H2O2, NaOH): first __________ adds to ________ substituted carbon (anti-mark's rule) and ________ adds to more sub. carbon; this happens simultaneously (aka ____________) and from the _________ face of the double bond (syn)

BH2; OH; same; syn

in hydroboration-oxidation reaction (1. BH3, 2.H2O2, NaOH): second __________ (remaining in flask after DB attacked B of BH3 and H adds to more sub C of DB) is converted into/replaced by __________ (when NaOH and H2O2 added); this is done in the _________ plane bc the reaction has a ________ stereoselectivity and enantiomers may be created (both will have either both wedges or both dashes on subs.)

OH

in hydroboration-oxidation reaction (1. BH3, 2.H2O2, NaOH): in the second step of the mechanism, BH2 is converted/replaced by __________ (*don't need to know exactly how this happens yet*)

electron deficient

in hydroboration-oxidation reaction (1. BH3, 2.H2O2, NaOH): the boron in BH3 is ___________ ____________ making it act as an electrophile (with partial positive charge) and gets attacked by _________ nucleophile on alkene while H from BH3 adds to DB

mark's rule

in the addition of HX, H2O, or ROH to an alkene, hydrogen adds to the carbon of the double bond having the greatest number of hydrogens

equal probability; more substituted; character; longer

in the case of a bromonium or chloronium ion derived from a symmetrical alkene (same amount of subs. on both sides), both carbons are attacked by H2O during halohydrin formation with ____________ ____________; in the case of unsymmetrical alkenes, the H2O attacks on the __________ _________ carbon because it has more carbocation _____________ and the C-X bond to the more substituted carbon of the halonium ion is __________ than the bond of the less substituted so breaking this bond is easier to open 3-membered ring

hyperconjugation

interaction of electrons in a sigma bonding orbital with the vacant 2p orbital of an adjacent positively charged carbon

electrophile

meaning electron loving, seeking a region of high electron density; electron sink that can accept a pair of electrons to form a new covalent bond; (lewis acid)

nucleophile

meaning nucleus loving; seeking a region of low electron density; can donate a pair of electrons to form a new covalent bond; (lewis base)

ring strain

rearrangement can also be done under other special circumstances such as where the relief of ________ _______ provides driving force or rearrangement

less; more

rearrangement is done to make _________ stable carbocations (such as secondary and primary) into ____________ stable carbocations (like tertiary)

acid-catalyzed hydration; more

rearrangements can also happen in _________-__________ ______________ of alkenes, when the carbocation formed in first step can rearrange to a more ___________ carbocation

rearrangement; OH, H; rearrangment; less

some of the same molecules can have multiple reaction conditions (such as oxymercuration-reduction and acid-catalyzed hydration- both add _______ and ______ product groups) except acid-catalyzed hydration can require carbocation ________________ which can mess up products hence making it __________ preferable as compared to oxymercuration-reduction

syn

stereochemistry in which groups add on same side of DB (both dashes, both wedges)

anti

stereoselectivity in which groups add on opposite sides of DB(one dash, one wedge)

hydration

the addition of water to alkene

bond dissociation energy

the amount of energy required to break a bond into two radicals in the gas phase at 25 degrees C, A-B-->A~ + B~

function; nucleophile; base

the difference between nucleophiles and bases is a difference of __________ in which you have to determine if a base acts as a ______________(measure of kinetics- rate of reaction) or as a _________ (measure of stability/pos of equilibrium- thermodynamics)

X; break; halogen; DB; bridged ion; two; positive

the first thing that happens during a halohydrin (as well as just addition of halogens) formation reaction (H2O and X2: Cl2 or Br2) the DB of the alkene attacks the one of the _______ atom's and this causes the bond between X-X to _______, at the same time this X atom attacks the ________ to create the _________ ________ intermediate; in this intermediate ion the X now has _______ lone pairs and a __________ charge

BDEreactants-BDEproducts=Hbreak-Hmake

the formula for calculating ΔHrxn is:

reduction

the gain of electrons; alternatively either the gain of hydrogen, loss of oxygens, or both (RIG- reduction is gain)

osmate

the intermediate formed during oxidation of alkene to glycol is ___________ (ester or cyclic)

molozonide

the intermediate formed during ozonolysis is called an ______________

oxidation

the loss of electrons; alternatively either the loss of hydrogens, the gain of oxygens, or both (OIL- oxidation is loss)

increase; stronger; stable

the net result of hyperconjugation is an _________ of electron density on the cationic carbon, thereby delocalizing the positive charge onto the adjacent alkyl groups; as more alkyl groups are bonded to the carbocation, the hyperconjugation effect becomes ____________ therefore making the carbocation more __________

inductive effect

the polarization of the electron density of a covalent bond resulting from the electronegativity of a nearby atom; this is one of the reasons why the more alkyl groups that are added to cationic carbon increases the stability of the cation because the positive charge is more delocalized with each group

H2O; more substituted; more

the second thing that happens during a halohydrin formation (different than addition of halogens) is __________ attacks the ________ __________ carbon of the bridged halogen ion and opens the three-memebered ring (the H2O attacks instead of the X because there is __________ of H2O than X in the flask)

oxidation of alkenes to glycol (vicinal diol)

what reaction is this?

oxymercuration-reduction

what reaction is this?

hydroboration-oxidation

what type of reaction is this?

frontside; backside; anti; opposite

when dealing with how to attack a three-membered ring ion formed as an intermediate (such as bromonium or chloronium) usually the first attack is from the _____________ therefore the next attack has to be from the ___________ which is what gives the product an ___________ stereoselectivity in that the groups are in ____________ planes (one dash, one wedge)

wedge; dashes; enantiomers

when forming products of electrophilic addition from intermediate, see if the electrophile forming bond with nucleophile could attack from the back (making it __________ orientation) or from the front (making it a __________ orientation) then see if a chiral center was created, if so then the products could be a pair of ______________ (could also be meso)

flask

when trying to do a mechanism for adding in multiple compounds, ask yourself what is in the _________ together after each step and see if these species react

it flips

when we flip a reaction, what happens to ΔH?

bridged halonium ion; opposite; anti; coplanar

when you add Br2 or Cl2 to a alkene, the intermediate that forms is a ___________ _____________ ________ with a positive charged X atom bonded to both carbons of the former DB; the additional Br then attacks from the ___________ side of the bridge to open up the 3-membered ring to give the _________ (stereochemistry) product which has the halogens as ____________ (in the same plane)

nucleophile; electrophile

whenever one compound uses its electrons to attack another compound, we call the attacker the ___________ and we call the compound being attacked the _______________

addition of halogens (Br-Bromination and Cl-Chlorination)

which reaction is this?

enthalpy; small

ΔH (which is ___________) can be used to predict spontaneity if ΔS is ___________