Visible light-initiated manganese-catalyzed hydrosulfonylation of alkenes

Strategies for the preparation of sulfones have received much attention because they have found widespread applications in the pharmaceutical, agrochemical, and materials science fields. Although the radical hydrosulfonylations of alkenes have provided a direct and powerful technique for sulfone synthesis, these protocols still suffer from some shortcomings, such as a limited alkene scope and the use of expensive photocatalysts and/or 4-mercaptophenol. Herein, we report a visible light-initiated manganese-catalyzed radical hydrosulfonylation technique using commercially available and relatively cheap sulfonyl chlorides as sulfonyl radical sources, which can expediently convert a wide range of alkenes to valuable sulfonyl-containing compounds under very mild reaction conditions. Besides a broad substrate scope (we disclose more than 50 examples), this practical strategy exhibits extraordinary functional-group tolerance and can be applied to the late-stage functionalization of complex drug derivatives. Importantly, compared to the existing methods for the photocatalytic hydrosulfonylation of alkenes, the current procedure avoids the usage of precious Ir-based photocatalysts and toxic 4-mercaptophenol, thus providing a green and sustainable alternative to alkene hydrosulfonylation. A visible light-initiated manganese-catalyzed radical hydrosulfonylation of a wide range of structurally diverse alkenes using commercially available and relatively cheap sulfonyl chlorides as sulfonyl radical sources is described.