STEREOSPECIFIC CROSS-COUPLING REACTIONS OF 3-ARYLSULFINYLPROPENOATES WITH ORGANOMETALLIC REAGENTS

(E)- or (Z)-3-arylsulfinylpropenoates have been reacted with several o rganometallic rea gents. Grignard reagents were found to promote only the complete substitution of the arylsulfinyl group in good yields up to 92%. The reaction followed a stereochemical course of retention of configuration with high values of stereospecificity (up to 99%) in mos t cases. The observations made are discussed in the light of current v iews concerning nucleophilic substitution at a vinyl carbon atom. The addition-elimination pathway is considered valid, whereas a route invo lving the formation of a sulfurane as an intermediate, followed by a l igand coupling, is considered less likely.