Page # 1
Addition of H-X to an Alkene - Electrophilic Addition Reaction
Possibility # 1
H H
H
protonation CHz cuz
H C H
C C notformed toounstable
H
1
H H
Possibility # 2
H
As
Br
protonation
Regioselective:
YES macroknominksoninionaleisomer
at
aurea
Stereoselective: NO
nucleophilic Br
Carbocation Rearrangement: YES attack
Reaction Summary:
Haloalkehl
Step1 PROTONATION
It goes to carbon of doublebond with mostprotons
NUCLEOPHILIC ATTACK
step 2
aBoor
x goestothemostcarbocation like carbocation followingcarbocation
rearrangement it necessary I
the halogengetsadded on to the more substitutedcarbon
Product
Example:
+ HCl
Cl I
, Page # 2
Acid Catalyzed Hydration of an Alkene
O H O
H O S O H
n
+ O proton
O + O S O H
H H transfer
O
UN H H
O
H
H C H protonation so H2O
C C
H
I
H H
H
GO nucleophilic
H H attack H O H
nucleophile
Alcohol
oo H H
iOH H O H I
O
deprotonation
I Oxonium
ion
Product
Reaction Summary:
Step 1 protonation of alkene to generate more stable
electrophilic carbocation
moleculeon
Step 2 attackof thenucleophilicH2O
createsan oxoniumion
Regioselectivity:
YES Markovnikov
alcohol
step3 deprotonation by abasegeneratesthe
OILGOESONMORE SUBSTITUTEDCARBON
FOLLOWSMARKOVNIKOV Stereoselectivity:NO racemic mixture
RACEMICMIXTURE FORMED IF THERE'S ACHIRALCENTER
Example: Carbocation Rearrangement:YES
OH
Cat H 2SO 4
N
H 2O racemic
, Acid Catalyzed Addition of an Alcohol to an Alkene Page # 3
H O
H O
O
S O H
n
+ H 3C O H H 3C O H O S O H
O O
CH 3 H
C O
H 3C CH2 H CH 3
H CHz
U
H 3C
I O H
monaonenaiti
Ester
H 3C O H
y CH3
A
deprotonan.ona
µy
f
Product
Regioselectivity: YES Markovnikov
Steroselectivity: NO Nh proceeds via planarcarbocation
Carbocation Rearrangement: YES
REMOVE AN H FROM THEACID
CATALYST
CH30 goes 0h MORE
SUBSTITUTED C
CH 3CH2OH 1 CHzCHOH
cat H 2SO 4
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