Visible-light-induced acylation of active olefins by 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.