Photoinduced Electron Transfer from Xanthates to Acyl Azoliums: Divergent Ketone Synthesis via N‐Heterocyclic Carbene Catalysis

Abstract

AbstractConsidering the prevalence of alcohols and carboxylic acids, their fragment cross‐coupling reactions could hold significant implications in organic synthesis. Herein, we report a versatile method for synthesizing a diverse range of ketones from alcohols and carboxylic acid derivatives via N‐heterocyclic carbene (NHC) catalysis. Mechanistic investigations revealed that photoexcited xanthates and acyl azoliums undergo single electron transfer (SET) under photocatalyst‐free conditions, generating NHC‐derived ketyl radicals and alkyl radicals. These open‐shell intermediates subsequently undergo the radical‐radical cross‐coupling reaction, yielding valuable ketones. Furthermore, this approach can be employed in three‐component reactions involving alkenes and enynes, resulting in structurally diverse cross‐coupled ketones. The unified strategy offers a unique opportunity for the fragment coupling of a diverse range of alcohols and carboxylic acid derivatives, accommodating diverse functional groups even in complex settings.