Catalyst‐Free Deaminative Functionalizations of Primary Amines by 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 alkylation (Giese), allylation, vinylation, alkynylation, thioetherification, and hydrodeamination reactions. The mild conditions are amenable to a diverse range of primary and secondary alkyl pyridiniums and demonstrate broad functional group tolerance. Electron donor–acceptor complexes between pyridinium‐activated primary amines and Hantzsch ester or triethylamine undergo catalyst‐free photoinduced single‐electron transfer with visible light. Fragmentation leads to alkyl radicals that could be intercepted with a variety of acceptors. This deaminative radical generation was applied to catalyst‐free Giese, allylation, vinylation, alkynylation, thioetherification, and hydrodeamination reactions.