Photoinduced Regioselective Sulfonylsulfination of Alkenes

Regioselective 1,2-dichalcogenation of alkenes has attracted significant attention in modern organic synthetic chemistry. While there are a plethora of methods to access alkene dichalcogenated architectures, sulfonylsulfination of alkenes is extremely challenging due to the inherent characteristics of the sulfur atom. Herein, a multicomponent fragment coupling of alkenes, sulfinates, and DABSO was developed to construct densely functionalized sulfonylsulfinated products, which are otherwise challenging to access, with broad substrate scope and group tolerance under mild and operationally simple conditions, using an inexpensive 100–1000 ppm organic photocatalyst. In addition, the protocol was applied to the late-stage functionalization of complex molecules, and the obtained products were converted into diverse downstream transformations to demonstrate their synthetic potential. Experimental and theoretical mechanistic investigations suggest that these reactions proceed through sequential sulfonyl and sulfinyl oxygen radical mutual transformations and radical–polar crossover coupling. This strategy provides access to previously inaccessible alkene sulfonylsulfinated products in good-to-high regio- and stereoselectivity, along with opening up previously unexplored synthetic directions.