Visible light-induced C-H sulfenylation using sulfinic acids

The visible light and Eosin B-catalyzed direct sulfenylation of sp(2) 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 sp(2) 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.