Ch 8 Alkene chemistry

what are the 3 rules with naming alkenes

suffix is ene

double bond gets priority over substituents when counting the carbon chain

use E + Z (trans/cis)

(z)-5-bromo-2-hexene > number before the parent chain indicates where the alkene starts

how do you name cycloalkenes whats the rule

double bond carbon should be 1 and 2, whichever order gives substituents lowest number

ALKENE REACTIONS

what is the foundational process of an addition reaction

breaking 1 pi bond to build 2 sigma bonds

ALKENE REACTIONS

entropy and enthalpy of addition reactions

both decrease: exothermic + less randomness (2 molecules → 1 molecule)

ALKENE REACTIONS

are addition reaction spontaneous

yes at lower temps

ALKENE REACTIONS

Halogenation Reactions: what do you do

add an H and a halogen (Cl, Br)

ALKENE REACTIONS

Halogenation Reactions: what are the steps for a symmetric alkene

pi bond goes to positive ion in reagent (H-Br/Cl)

loss of pi bond makes Carbon 2 a carbocation

negative ion goes on carbon two

ALKENE REACTIONS

Halogenation Reactions: what is the rule for asymmetric alkenes

Markovnikov’s Rule: H is added to double bond carbon that has more hydrogens (less substituted)

ALKENE REACTIONS

Halogenation Reactions: what is anti-markovnikov’s rule

adding hydrogen to carbon with less hydrogens on it (more substituted carbon)

ALKENE REACTIONS

What do you do when there is chiral centers

add wedge and dash + En

ALKENE REACTIONS

Acid Catalyzed Hydration: what is the process of this

adding H and OH

ALKENE REACTIONS

Acid Catalyzed Hydration: what is the reagent used in this

H2SO4, H2O → H3O+

ALKENE REACTIONS

Acid Catalyzed Hydration: how do you do this with symmetric alkenes

remove double bond → add OH to one carbon add H to other

ALKENE REACTIONS

Acid Catalyzed Hydration: how do you do this with asymmetric alkenes step 1

pi bond goes to the H+ → H goes to less substituted carbon

ALKENE REACTIONS

Acid Catalyzed Hydration: how do you do this with asymmetric alkenes step 2

check for carbocation rearrangement

ALKENE REACTIONS

Acid Catalyzed Hydration: how do you do this with asymmetric alkenes step 3

lone pair from H2O as a reagent goes to the carbocation

ALKENE REACTIONS

Acid Catalyzed Hydration: how do you do this with asymmetric alkenes step 4

deprotonation of an H on the H2O added to the carbocation spot using another H2O as reagent

ALKENE REACTIONS

Oxymercuration-Demercuration: what is the process of this and whats special about this

adding H and OH

but no carbocation rearrangement

ALKENE REACTIONS

Oxymercuration-Demercuration: what is the reagent for this

Hg(OAC)2,H2O / NaBH4

ALKENE REACTIONS

Oxymercuration-Demercuration: step 1 of this process

lone pair attacks the positive Hg, Lone pair on the Hg comes attacks back at the carbons

ALKENE REACTIONS

Oxymercuration-Demercuration: step 2

Hg - OAC forms 2 bonds with that main carbon chain making a triangle

ALKENE REACTIONS

Oxymercuration-Demercuration: step 3

Using H2O as a reagent, its lone pairs attacks the more substituted carbon of that triangle, releasing the Hg on that attacked side and attaching H2O to that carbon

ALKENE REACTIONS

Oxymercuration-Demercuration: step 4

using H2O as a reagent again to deprotonate that H2O

ALKENE REACTIONS

Oxymercuration-Demercuration: step 5

NaBH4 as a reagent to turn the Hg(OAC) into H

ALKENE REACTIONS

What is Syn Addition vs Anti Addition

added groups from the same side (dash and dash or wedge and wedge)

added from opposite sides

ALKENE REACTIONS

Hydroboration-Oxidation: what are the key points of this

adding H + OH

anti markovnikov addition

syn addition

ALKENE REACTIONS

Hydroboration-Oxidation: what is the reagent used in this

BH3 THF / H2O2, NaOH

ALKENE REACTIONS

Hydroboration-Oxidation: how do you do this (he didn’t give mechanism so just recognize it)

add H to more substituted carbon in alkene, add OH to other one

if one stereocenter, throw wedge or dash (also turn the existing methyl if there is one to opposite) + En
if two stereocenter, throw wedge or dash on both the same + En

ALKENE REACTIONS

Catalytic Hydrogenation Reaction: what are the main points of this

Adding H+H

Syn addition

use of catalyst

ALKENE REACTIONS

Catalytic Hydrogenation Reaction: what are the catalysts in this

Pd Pt Ni

ALKENE REACTIONS

Catalytic Hydrogenation Reaction: what is the reagent in this

H2

ALKENE REACTIONS

Catalytic Hydrogenation Reaction: What is the main use of this reaction

to convert an alkene into an alkane

ALKENE REACTIONS

Catalytic Hydrogenation Reaction: how do you do this (no mechanism just do it)

just add hydrogen to both carbons of the double bond

if they alr have groups on them, turn them both into dash or wedge and turn the other group into the opposite

ALKENE REACTIONS

Halogenation: what is the main part of this

adding Cl2 or Br2

anti addition

ALKENE REACTIONS

Halogenation: how do you do this (just refresh the mech soon)

add one halogen to each carbon, one dash one wedge

ALKENE REACTIONS

Halohydrin Formation: what is the main feature of this and the reagent

anti addition

Halogen (Br2/Cl2) / H2O

ALKENE REACTIONS

Halohydrin Formation: step 1 of this

pi bond attacks positive of the halogen pair and that becomes a triangle bond with the double bond carbons (which is now single)

ALKENE REACTIONS

Halohydrin Formation: step 2

lone pair of H2O attacks the more substituted carbon in there, separating the halogen triangle, H2O ends up on the carbon it attacked

ALKENE REACTIONS

Halohydrin Formation: step 3

H2O becomes the opposite direction the halogen was (dash→wedge)

ALKENE REACTIONS

Halohydrin Formation: step 4

add another H2O reagent to deprotonate the H2O

end result is halogen on one carbon in one direction, H2O on the other carbon in the opposite direction

ALKENE REACTIONS

Anti-Dihydroxylation: what groups are added to this

2 OH groups in an anti fashion (wedge and dash)

ALKENE REACTIONS

Anti-Dihydroxylation: what is the reagent

peroxy acid: m-CPBA / H3O+

ALKENE REACTIONS

Anti-Dihydroxylation: what is an intermediate in this reaction

epoxide: 2 carbon attached to 1 O in a ring formation

ALKENE REACTIONS

Anti-Dihydroxylation: