Nickel-Catalyzed Cross-Dehydrogenative Coupling of Aldehydes and Alkenes toward Skipped Enones

The direct transformation of C-H bonds into C-C bonds via cross-dehydrogenative coupling (CDC) represents a powerful strategy in synthetic chemistry, enabling streamlined bond construction without the need for prefunctionalized substrates. While traditional CDC approaches rely on polar mechanisms and preactivation of one of the C-H partners, recent advances have introduced radical-based strategies that employ a hydrogen atom transfer (HAT) approach to access carbon-centered radicals from unactivated substrates. Herein, we report a nickel-catalyzed CDC reaction between aldehydes and alkenes for the synthesis of skipped enones, leveraging aryl radicals as intermolecular HAT agents. The transformation proceeds via the in situ generation of aryl radicals from aryl bromides, which mediates HAT from both the aldehydic and allylic C-H bonds to generate acyl and allylic radicals, respectively. These radicals are then engaged in a nickel-catalyzed radical-radical cross-coupling to deliver the skipped enone products. This method demonstrates a broad substrate scope, high chemoselectivity, and excellent tolerance to diverse functional groups, providing a versatile platform for late-stage functionalization and synthesis of valuable skipped enone scaffolds.