Air Induced Phosphoryl Radical Mediated Stereoselective Hydrosulfonylation of Alkynes via Halogen Atom Transfer: Ingress of Z -Vinyl Sulfones.

The phosphoryl radical is well-known to participate in addition reactions with alkenes/alkynes. Here, we report a novel reaction mode of the phosphoryl radical where it participates in halogen atom transfer (XAT) with electron deficient vinyl halides instead of a facile addition reaction. Nevertheless, in comparison with aryl and alkyl halides, the exploitation of vinyl halides into a carbon radical via XAT is quite rare. This protocol provides an opportunity for direct hydrosulfonylation of numerous internal as well as terminal alkynes to get various Z -vinyl sulfones under environmentally benign conditions. Generation of the phosphoryl radical in the open air, water as a solvent, excellent functional group compatibility, and exceptional chemoselectivity are the attractive features of the present methodology.