Visible-Light-Triggered Directly Reductive Arylation of Carbonyl/Iminyl Derivatives through Photocatalytic PCET.

The first visible-light-mediated radical-radical cross-coupling strategy that enables the direct arylation of carbonyl/iminyl derivatives in the presence of Et3N has been realized. Such an atom-economical protocol furnishes a broad scope of arylation products such as secondary/tertiary alcohols and amines via a PCET process that facilitates the challenging reduction of C═X (X = O, N). Mechanistic investigation indicates two photocatalytic redox cycles were involved in the process, and Et3N was proved to serve as a dual reductant and proton donor. Moreover, the isolated byproducts and controlled experiments could be considered as powerful supporting evidence for our hypothesis.