Efficient Synthesis of α,β-Epoxy Carbonyl Compounds in Acetonitrile: Darzens Condensation of Aromatic Aldehydes with Ethyl Chloroacetate

The Darzens reaction of ethyl 2‐chloroacetate (1) with aromatic aldehydes 2 in the presence of polymer‐supported or nonsupported quaternary ammonium salts proceeds under mild conditions by phase‐transfer catalysis to give the corresponding epoxides 3 in satisfactory yields (Tables 1 and 2). With both MeCN as solvent and polystyrene‐supported catalysts, diastereoselective Darzens reactions proceed in excellent yields and short times, with a fair degree of stereoinduction.