Q19P - Organic Chemistry (Mcmurry)

Question

What ester and what Grignard reagent might you start with to prepare the following alcohols?

a.

b.

c.

Step-by-Step Solution

Answer

Reactants needed are:

a. methyl benzoate and Methyl magnesium bromide 

b.

methyl acetate and aryl magnesium bromide 

c.

methyl pentanoate and ethyl magnesium bromide

Step 1: Ester and Grignard reagent for Preparing Alcohol A

Esters react with 2 equivalents of a Grignard reagent to yield a tertiary alcohol in which two of the substituents are identical. So, methyl benzoate and Methyl magnesium bromide are needed to prepare the given alcohol.

Step 2: Ester and Grignard reagent for Preparing Alcohol B

For preparing tertiary alcohol given in b methyl acetate and aryl magnesium bromide are needed.

 

Step 3: Ester and Grignard reagent for Preparing Alcohol C

For preparing tertiary alcohol given in c methyl pentanoate and ethyl magnesium bromide are needed.