Synthesis of Vinyl Sulfoxides Using Sulfinyl Chlorides and Olefins

A general method for synthesis of vinyl sulfoxides, using sulfinyl chlorides and olefins as starting materials and DBU as an HCl scavenger, has been developed. Vinyl sulfoxides were obtained from the ZnCl2 catalysed addition of sulfinyl chlorides to olefins followed by the elimination with DBU. However, the direct reaction of sulfinyl chlorides with olefins in the presence of DBU, usually leads to generation of vinyl sulfones. The sulfonyl radicals generated from the DBU-mediated disproportionation of the sulfinyl radicals undergo addition-elimination reaction with olefins to give vinyl sulfones.