Visible-light-induced acylation of active olefins by a C–C bond cleavage/Smiles rearrangement radical relay strategy via EDA complexes

Abstract

Photoinduced C–C bond activation of acyl oxime esters to generate aliphatic and aryl acyl radicals typically requires noble metal photocatalysts or synthetically elaborate organic dyes. In contrast, electron donor–acceptor (EDA) complex photochemistry has emerged as a powerful strategy in organic synthesis, offering operational simplicity and the potential to generate radicals via single electron transfer under visible-light irradiation without any photocatalysts. Herein, we report the first visible-light-induced EDA-complex-promoted acylation of 1,8-enynes through a C–C bond cleavage/Smiles rearrangement radical relay strategy. This photocatalyst- and initiator-free protocol aligns with green chemistry goals by avoiding stoichiometric oxidants, minimizing synthetic steps, and using visible light as a traceless energy source. The system tolerates both aliphatic and aryl acyl radicals simultaneously, enabling efficient access to a variety of acylated nitrogen-containing heterocycles in good to excellent yields. Notably, the transformation embodies high step-economy via the concurrent cleavage of four covalent bonds and formation of four new bonds in a single photochemical operation.