Relay Dual Catalysis: Photoredox and NHC-Catalyzed Cross-Double C-H Functionalizations of Aldehydes and Alkenes

Direct functionalizations of two distinct inert C-H bonds represent the most ideal ways to construct C-C bonds. Herein, we report an intermolecular vinylation of aldehydes using alkenes as the vinylating reagents through sequential two-fold C-H functionalizations. The merging of visible light and NHC-catalysis allows for the direct coupling of alkenes with aldehydes through an unprecedented relay dual catalysis enabled cross-dehydrogenative coupling mechanism. The use of diphenoquinone is essential for the success of this reaction, which plays an intriguing two-fold role in the reaction, as both an electron acceptor as well as a radical reservoir for the radical coupling enabling C-C forming-process.