Oxidative Cyclization Synthesis of Tetrahydroquinolines and Reductive Hydrogenation of Maleimides under Redox-Neutral Conditions.

A redox-neutral reaction without using any external oxidant and reductant in one pot is described. By combining a Ru(bpy)32+ photocatalyst and cobaloxime catalyst, a number of tertiary anilines can be oxidized by Ru(bpy)32+ to realize oxidative cyclization of tetrahydroquinolines, and the electron and proton eliminated from the substrate anilines are captured by a cobaloxime catalyst to achieve hydrogen transfer in situ to maleimides, in good to excellent yields, under redox-neutral conditions.