Metal-free photoinduced-radical hydrocyclization of 2-isocyanides: a unified synthetic approach to facilely assemble diverse N-heteroarenes†

α-Unsubstituted aromatic N-heterocycles are a family of broadly used building blocks that play an integral role in drugs, agrochemicals, and materials. However, accessing diverse α-unsubstituted N-heteroarenes in a single strategy is challenging but highly desirable. Thus, a novel and unified photoinduced-radical hydrocyclization of 2-isocyanides is described for rapid assembling of various N-heteroarenes. The reaction features mild and sustainable reaction conditions with broad substrate scope and excellent functional group compatibilities. The potential synthetic utilization is highlighted by the facile synthesis of some biologically active natural alkaloids. Moreover, the mechanism studies indicated that the single-electron reduction/protonation is the key process of the transformation.