Chapter 21, Problem 81PP

Interpretation Introduction

Interpretation:

Mechanism for the given reaction should be identified.

Concept introduction:

Carbonyl compound when treated with LDA (Lithium diisopropylamide) undergoes deprotonation at the $\alpha$ carbon to form enolate. The resulting enolate ion is resonance stabilized by carbon and oxygen atom. The resonance stabilized intermediate undergoes reaction with other molecule of carbonyl (same or different) to form the respective products.  If LDA is used as a base the less substituted $\alpha$ carbon is deprotonated due to steric hindrance.

• Deprotonation of $\alpha$ carbon to form enolate
• Nucleophilic attach of enolate
• Protonation of $\alpha$ carbon to final product