Question:Outline two different ways that butan-2-one can be prepared from a nitrile and a Grignard reagent.

Nitriles react with Grignard reagents to form a compound with a new C-C bond and a ketone group. The alkyl or aryl group of the Grignard reagent acts as the nucleophile and attacks at the electrophilic carbon of the cyanide group.

The mechanism for the reaction with the Grignard reagent is given below:

Reaction with Grignard reagent

The structure of butan-2-one is given below:

butan-2-one

You can prepare butan -2-one from a nitrile and a Grignard Reagent in two ways. The

retrosynthetic analysis is shown below:

Retrosynthetic analysis of butan-2-one

Thus, the synthetic pathway based on the nitriles and Grignard reagents obtained is as follows:

Synthesis of butan-2-one