Catalyst-Free Deaminative Functionalizations of Primary Amines via Photoinduced Single-Electron Transfer

The use of pyridinium‐activated primary amines as photoactive functional groups for deaminative generation of alkyl radicals under catalyst‐free conditions is described. By taking advantage of the visible‐light absorptivity of electron donor–acceptor complexes between Katritzky pyridinium salts and either Hantzsch ester or Et₃N, photoinduced single‐electron transfer could be initiated in the absence of a photocatalyst. This general reactivity platform has been applied to deaminative alkylations (Giese), allylations, vinylations, alkynylations, and thioetherifications. The mild conditions are amenable to a diverse range of primary and secondary alkyl pyridiniums and demonstrate broad functional group tolerance.