Stereoselective thiosulfonylation of alkynes using sodium thiosulfate as a sulfur transfer agent to access bis-(Z)-vinyl sulfones.

Here, we describe a novel and untapped reactivity profile of sodium thiosulfate, where it acts as an odourless, inexpensive and green sulfur surrogate equivalent to hydrogen sulfide (H2S) for in situ-generated iodo vinyl sulphones under metal and acid-free conditions. However, in contrast to acetic anhydride and alkyl halides, the utilisation of Na2S2O3 as a sulfurating agent with vinyl halides is quite rare. This methodology opens an avenue for the direct thiosulfonylation of a wide range of terminal or internal alkynes to get numerous bis (Z)-vinyl sulphones decorated with vicinal thioethers under environmentally benign conditions.