Question

Tertiary alcohols can be formed by the reaction of dimethyl carbonate [(CH₃O)₂C$=$O ] with excess Grignard reagent. Draw a stepwise mechanism for the following transformation.

Short answer

Answer

Step 1:

Step 2:

Step 3:

Step-by-step solution

Step-by-Step Solution  Step 1: Grignard reagents

Grignard reagents are highly reactive towards electrophiles due to their nucleophilic nature. They undergo a nucleophilic addition reaction with carbonyl compounds to give corresponding alcohol.

Transformation mechanism

• The elimination of the methoxy group follows the nucleophilic addition of Grignard reagent at carbonyl group.

Reaction with first mole of Grignard reagent

• The second molecule of Grignard reagent attacks the carbonyl carbon, and the methoxy group is eliminated similarly.

Reaction with second mole of Grignard reagent

• The third molecule of Grignard reagent attacks the carbonyl carbon followed by acid hydrolysis to form triphenyl methanol.

Reaction with third mole of Grignard reagent and hydrolysis