EDA complex-enabled annulation

Photoinduced transformations employing an electron donor-acceptor (EDA) complex can eradicate the requirement of an external photocatalyst. The EDA complex produced from the reactants, upon light absorption, induces reactivity via a single electron transfer (SET) from the donor to the acceptor. The resulting reactive radical species could be used as effective synthons for novel synthetic transformations. In fact, the recent advent of sustainable protocols based on EDA photochemistry facilitates the formation of diverse molecular architectures. This review article summarizes the last five years' (2021-2025) progress in EDA-enabled photocyclization for constructing various heterocyclic and carbocyclic skeletons under mild reaction conditions. Mechanistic aspects of the reactions are highlighted for better understanding of the reaction pathways.