Answer :
Final answer:
Excess Grignard reagent reacts with diethyl carbonate to form a tertiary alcohol after hydrolysis, involving nucleophilic attack on the carbonyl carbon and subsequent protonation of the intermediate.
Explanation:
The reaction of an excess Grignard reagent with diethyl carbonate leads to the formation of a tertiary alcohol upon hydrolysis. When diethyl carbonate, which has the structure O=C(OC2H5)2, reacts with a Grignard reagent (RMgX), the nucleophilic carbon attacks the electrophilic carbonyl carbon, breaking the C=O double bond, and forming an alkoxide ion intermediate.
After hydrolysis, this intermediate yields a tertiary alcohol, R3COH. These types of reactions are part of a broader class of reactions where Grignard reagents attack carbonyl groups to form alcohols after protonation by an acid. The specific alcohol that is formed depends on the nature of the carbonyl compound that the Grignard reagent is reacting with. For instance, formaldehyde will yield primary alcohols, aldehydes will yield secondary alcohols, and ketones will yield tertiary alcohols.
