Knoevenagel Condensation: Carbonyl + Active Methylene → Alkene (Mechanism + Uses)

Learn the Knoevenagel condensation: deprotonation of an active methylene, addition to carbonyl, dehydration to alkene, and how to predict products.

• Reaction: Carbonyl + active methylene → substituted alkene
• What it does: Forms C=C next to electron-withdrawing groups
• Typical reagents: Base (amines, piperidine) + malononitrile/malonic ester
• Key intermediate: Stabilized carbanion / β-hydroxy intermediate
• Driving force: Conjugated alkene formation; dehydration
• Exam type: Condensation
• Exam type: Predict product