Photoexcited Cyanohydrin Anions Enable Redox-Neutral Acylarylation of Olefins

The direct photoexcitation of anions generated by deprotonation of C-H bonds under visible light has been less explored. Herein, we report that cyanohydrins can be photoexcited by visible light irradiation upon deprotonation. The photoexcited cyanohydrin anions demonstrate exceptional reducing capabilities, facilitating the single-electron transfer to aryl halides under mild conditions. The generated persistent cyanohydrin radicals serve as versatile acyl radical precursors for redox-neutral three-component acylarylation of olefins with a broad substrate scope. This study establishes cyanohydrin anions as a new class of photoactive species, offering a sustainable strategy for C-C bond formation without external oxidants or transition metals.