Photocatalytic amidyl radical formation: mechanistic insights and reactivity advances

Amidyl radicals, as versatile N-centered radical intermediates, have emerged as pivotal building blocks in modern organic synthesis, enabling the construction of diverse C-N, C-C, and other carbon-heteroatom bonds under mild conditions. Over the past decade, visible-light photocatalysis has revolutionized the generation of amidyl radicals, overcoming the limitations of traditional methods that rely on harsh reaction conditions or stoichiometric oxidants/reductants. This review summarizes the recent advances in photocatalytic amidyl radical formation, focusing on mechanistic insights and reactivity patterns. The generation pathways of amidyl radicals are systematically categorized based on the cleavage of N-H, N-X (X = F, Cl, Br, I), N-N and N-O bonds, involving key processes such as single-electron transfer (SET), proton-coupled electron transfer (PCET), electron donor-acceptor (EDA) complex activation, and halogen atom transfer (XAT).