2. Knoevenagel Reaction
• Condensation between active methylene group and carbonyl group in the
presence of a base to form α-β unsaturated acid.
• Active methylene group:- compounds that possess methylene bridge which is
present between two strong electron withdrawing groups.Thus these compounds
form carbanions easily.
• Bases:- pyridine, piperidine, NH3/EtOH.
• Modification of aldol condensation
6. Reformatsky Reaction
• A condensation reaction of carbonyl compounds with α-halo-ester using metallic
zinc to form β- hydroxyl-esters.
• Solvent used are usually- benzene, ether or a benzene-ether mixture.