Chapter 23, Problem 23.71P

Interpretation Introduction

Interpretation: The product formed by the treatment of compound A with LDA followed by ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{I}$ is to be predicted. The multistep method for the conversion of A to B is to be devised.

Concept introduction: Lithium diisopropylamide (LDA) is a sterically hindered strong base. In an unsymmetrical ketone, it abstracts hydrogen from least substituted carbon to form kinetic product.

Alkylation of aldehydes and ketones takes place in the presence of a strong base. The use of appropriate base, solvent and temperature can yield one major product regioselectively. The first step is abstraction of proton and second step is attack of electrophile to form alkylated product.