Chapter 8.6, Problem 8.29P

Interpretation Introduction

Interpretation:

Major product has to be predicted for the given reaction.

Concept Introduction:

Alkylation of enolate can be done using alkyl halides.  The ketone is treated with lithium diisopropylamide, where an enolate is formed.  The formed enolate attack the alkyl halide to install the alkyl group at the alpha position.  Alkylation of enolate is an ${\text{S}}_{\text{N}}\text{2}$ reaction.  This reaction takes place only when primary halide is used. If a secondary halide is used, elimination takes place.  More substituted enolate will be more stable than the less substituted one.  Therefore, the alkylation happens in the less substituted enolate as it forms faster.  LDA reacts with ketone to give the kinetic enolate which is the less‑substituted enolate.  An example for this reaction is,