Photoinduced Amination of Endocyclic 1-Azaallyl Radicals

A catalyst-free method has been discovered based on photoexcited electron donor–acceptor complexes to generate an iminyl radical and endocyclic 1-azaallyl radicals, elusive intermediates that have never been reported in synthesis. The two radicals then combine and, following reduction, ultimately provide unprotected 2-(hetero)aryl-3-aminopiperidines. This reaction expands the knowledge and synthetic application of endocyclic 1-azaallyl synthons with an intrinsic ring strain.