Method for preparing intermediates for the synthesis of steroid side chains in optically active form

摘要

This invention provides a novel method for the preparation of optically active arylalykylsulfone derivatives, having a chiral center in the alkyl moiety in either the (R)- or the (S)-configuration. These optically active sulfones find use in the stereospecific synthesis of steroid or vitamin D compounds having chiral center at either carbon 24 or carbon 25 of the side chain. The method comprises the steps of reacting an optically active sulfinate ester having a chiral center at sulfur with a racemic alkyl Grignard reagent to obtain a mixture of diastereomeric sulfoxides, separating the mixture of diastereomeric sulfoxides, and oxidizing separately each of the diastereomers to obtain the desired optically active sulfone.