Visible-Light Photoredox-Catalyzed Reductive Coupling of Heteroaryl Chlorides with Alkenes.

We have developed a photocatalytic reductive system for the coupling of heteroaryl chlorides with alkenes, wherein the alkenes act as alkylating reagents. The mechanism involves two key single-electron reduction steps: first, activation of the C-Cl bond; and second, reduction of the resulting benzylic radical to a benzylic carbanion. This strategy enables efficient activation and alkylation of aryl C-Cl bonds.