The document summarizes the Knoevenagel and Reformatsky reactions. The Knoevenagel reaction is a condensation between an active methylene group and a carbonyl group in the presence of a base to form an α-β unsaturated acid. The Reformatsky reaction is a condensation of a carbonyl compound with an α-halo-ester using metallic zinc to form a β-hydroxyl-ester. Both reactions involve the formation of new carbon-carbon double bonds through a cyclic transition state.

1. KNOEVENAGEL & REFORMATSKY
REACTION
BY- ARUSHI SAHA

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

5. α-β unsaturated dibasic acid

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.

7. α-bromo-ester

8. Cyclic
transition
state
β- hydroxyl-ester
Step
2:
Formation
of
β-
hydroxyl-ester

9. ThankYou!