Nickel-Catalyzed Reaction between Vinyl Azides and an Alkyl Sulfonyl Radical Generated from DMSO: Rapid Access to β-Keto Sulfones

A sustainable method for the construction of valuable β-keto sulfones lies in the reaction between vinyl azides and the alkyl sulfonyl radical generated from the low-cost and comparatively steady bulk chemical dimethyl sulfoxide (DMSO) that has been developed. This strategy features mild and economical reaction conditions using inexpensive NiCl2 as the catalyst and H2O2 as the green oxidant. The conversion occurs through a sequence of ordered processes consisting of a sulfonyl radical addition, denitrogen, hydrogen abstraction, and hydrolysis. Mechanistic studies indicate that sulfinic acid produced from DMSO plays an essential role in the reduction of Ni(III). The sensitivity assessment and gram-scale experiments proceed smoothly to demonstrate the robustness and practicality of this protocol.