SYNTHESIS OF OPTICALLY ACTIVE BETA-HYDROXY ESTER AND OPTICALLY ACTIVE BETA-HYDROXY THIOESTER

摘要

PURPOSE:To obtain the titled compound in one step without using optically active starting substance, by reacting a ketene compound with a ketone in the presence of an optically active diamine derived from proline, etc., a Lewis acid and a tin (II) alcoholate. CONSTITUTION:The objective compound of formula IV or V can be produced by reacting a ketene compound of formula II (R1 and R2 are H, halogen, alkyl, aryl, etc.) with a compound of formula III (R4 and R5 are H, alkyl, aryl, furyl, etc., provided that R4 and R5 are not H at the same time) in a solvent at -100-0 deg.C, preferably -100--45 deg.C in the presence of (A) an optically active diamine derived from proline compound, e.g. a compound of formula I (R17-R20 are H, alkyl, aryl, etc.), (B) a Lewis acid and (C) a tin (II) alcoholate or tin (II) thiolate of formula Sn(X1R3)2 (X1 is 0 or S; R3 is alkyl, allyl, aryl or pyridyl).