Aerobic Visible-Light Photoredox Radical C–H Functionalization: Catalytic Synthesis of 2-Substituted Benzothiazoles

An aerobic visible-light driven photoredox catalytic formation of 2-substituted benzothiazoles through radical cyclization of thioanilides has been accomplished. The reaction features C-H functionalization and C-S bond formation with no direct metal involvement except the sensitizer. The reaction highlights the following: (1) visible-light is the reaction driving force; (2) molecular oxygen is the terminal oxidant, and (3) water is the only byproduct.