OPTICALLY ACTIVE β-HYDROXY-α-BROMO-α-FLUORO CARBOXYLIC ACID ESTER, PROCESS FOR CATALYTIC ASYMMETRIC SYNTHESIS THEREOF, 2-BROMO-2-FLUOROKETENE SILYL ACETAL, AND PROCESS FOR PRODUCING THE SAME

摘要

A novel, optically active β-hydroxy-α-bromo-α-fluoro carboxylic acid ester which is thought to be useful as an intermediate for a physiologically active substance; a process for catalytically synthesizing this optically active substance in a high asymmetric yield; a novel 2-bromo-2-fluoroketene silyl acetal useful as an intermediate for this optically active substance; and a process for synthesizing the same. The novel 2-bromo-2-fluoroketene silyl acetal is obtained by reacting a dibromofluoroacetate with a silyl halide compound. The novel, optically active β-hydroxy-α-bromo-α-fluoro carboxylic acid ester can be catalytically obtained through asymmetric synthesis by reacting the 2-bromo-2-fluoroketene silyl acetal with an aldehyde in the presence of a catalytic amount of a chiral Lewis acid.