Stereoselective Synthesis of (Z)-β-Chlorovinyl Sulfones by Addition of Sulfonyl Chlorides to Acetylenes

The addition reaction of sulfonyl chlorides with acetyl­enes in the presence of a copper salt is described. The reaction proceeds in toluene in the presence of CuCl with Me2S as the additive to afford only (Z)-β-chlorovinyl sulfones in moderate to excellent yields.