Photoredox Mediated Acceptorless Dehydrogenative Coupling of Saturated N-Heterocycles

We report herein a direct unsymmetric coupling and controllable aromatization reaction of saturated N-heterocycles enabled by synergistic photoredox and acid catalysis. The reaction furnishes C2–C3 connected biheterocycles in a highly chemo- and regioselective manner under rather mild conditions. Mechanistic studies indicated that the reaction proceeded via enamine-iminium coupling leading to exclusively C2–C3 connection.