Process for the preparation of (3R, 4S) -1- (4-fluorophenyl)-3 (S) -hydroxy-3- (4-fluorophenyl) propyl-4- (phenylmethoxy) phenyl -2-azetidinone

摘要

PROBLEM TO BE SOLVED: To provide a method for effectively manufacturing high purity (3R,4S)-1-(4-fluorophenyl)-[3(S)-hydroxy-3-(4-fluorophenyl)propyl]-[4-(phenylmethoxy)phenyl]-2-azetidinone with reduced contents of specific impurities and enantiomers.SOLUTION: When a benzyl protective body is manufactured by reacting a benzyl protective keto body and borane in presence of a CBS catalyst, the benzyl protective keto body is injected under a condition with co-existing a part of borane of needed amount in a reaction system in advance and remaining borane is added later to conduct the reaction.SELECTED DRAWING: None