Visible-Light Photoredox Catalysis: Aza-Henry Reactions via C-H Functionalization

We report the application of visible-light photoredox catalysis for the formation of C-C bonds between tertiary N-arylamines and nitroalkanes via an oxidative aza-Henry reaction. In the presence of I mol % Ir(ppy)(2)(dtbbpy)PF6, efficient coupling of nitroalkanes with in situ-generated iminium ions provides the desired products in up to 96% yield. Mechanistic studies suggest that reductive quenching of the Ir3+ excited state by the tertiary amine leads to the ammonium radical cation, with subsequent catalyst turnover (Ir2+ --> Ir3+) likely effected by atmospheric oxygen.