Visible light along with 1 mol% eosin Y catalyzed the direct oxysulfonylation of alkenes with sulfinic acids via a photoredox process which has been developed at room temperature under transition-metal-free conditions. The present reaction provides a highly efficient approach to diverse β-ketosulfones in moderate to good yields. It should provide a promising synthesis candidate for the formation of diverse and useful β-ketosulfone derivatives in the fields of synthetic and pharmaceutical chemistry.

The visible light and Eosin B-catalyzed direct sulfenylation of sp² C–H bonds with sulfinic acids through a photoredox process has been demonstrated at room temperature under transition metal-free conditions for the first time. Diverse heteroaryl sulfides were obtained in moderate to good yields. This is the first example of the sulfenylation of sp² C–H bonds using arylsulfinic acids as odorless sulfur reagents under visible light-induced conditions. More interestingly, the reductive products could be obtained under visible light-induced oxidative conditions. This protocol demonstrates a new model for C–S bond formation, which serves as a novel approach toward the synthesis of heteroaryl sulfides.