Enolate Alkylation (LDA): α‑Alkylation of Carbonyls (Mechanism + Kinetic Control)

Master enolate formation with LDA and SN2 alkylation at the α-carbon. Kinetic vs thermodynamic enolates, electrophile scope, and pitfalls.

• Reaction: Carbonyl → α-alkylated carbonyl
• What it does: Forms C–C bonds at the alpha position
• Typical reagents: 1) LDA, THF, −78°C 2) 1° alkyl halide
• Key intermediate: Lithium enolate
• Driving force: Strong base forms enolate; SN2 forms new C–C bond
• Exam type: Regioselectivity (enolates)
• Exam type: SN2 vs E2