91Ó°ÊÓ

Alcohols are synthesized from Grignard reagents (R-MgX). When ketones are treated with Grignard reagents, the product formed is always tertiary alcohol. The intermediate formed in this reaction is an alkoxide ion, and it further gets protonated by${\mathrm{H}}_{\mathrm{3}}{\mathrm{O}}^{\mathrm{+}}$.

(a) In this reaction, methylmagnesium bromide is a Grignard reagent, and it reacts with a ketone to give tertiary alcohol as a product.

Addition of methylmagnesium bromide to cyclopentanone

(b) In this reaction, when methylmagnesium bromide (Grignard reagent) is added to benzophenone, the product obtained is a tertiary alcohol. The –OH and methyl group is attached in place of the ketone group in the product.

Addition of methylmagnesium bromide to benzophenone

Addition of methylmagnesium bromide to 3-Hexanone