Download Discussion Worksheet #10 Formation of Alcohols Skill 1: Functional

Discussion Worksheet #10
Formation of Alcohols
Skill 1: Functional group transformations for alcohols


Alcohols can be made through addition, substitution or elimination mechanisms
There are ways to control regiochemistry and stereochemistry with alcohol formation
Problem 1: Provide the reagents necessary for formation of these alcohols.
Problem 2. Provide a mechanism for each of these reactions based on the reagents from problem
1.
Br
OH
HO-
+
OH
OH
H
O
H
B
OH
H
H
OH
OCH3
OH
O
OCH3
Skill 2: Predict the products of Grignard reactions OH
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
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Reaction of Grignard with an aldehyde (except formaldehyde) leads to a secondary
alcohol
Reaction of a Grignard with a ketone gives a tertiary alcohol
Grignard reagents react with esters twice to form tertiary alcohols
Problem 3: Predict the products of each Grignard reaction. Include stereochemistry where
necessary.
OH
1. CH3MgBr
2. acid quench
O
1. CH3MgBr
O 2. acid quench
OCH3
1. CH3MgBr
O 2. acid quench
OH
1. PhMgCl
2. H+
O
I
1. Mg, ether
2. CH3CH2CHO
3. H+
OH
Skill 2: Grignard in retrosynthesis 
Plan a Grignard retrosynthesis if you need to make a carbon-carbon bond next to a
hydroxyl group
Problem 4: Provide the necessary reagents
Problem 5. Plan two alternative syntheses involving Grignard reagents for each of these
compounds. If two syntheses are not possible, explain. In which cases could an ester be used as
the starting material?
1. xs CH3Ch2MgI
2. H3O+
MeO
1. CH3CH2MgBr
2. H3O+
O
O
OH
O
OH
1. CH3MgBr
2. H3O+