Photoinduced Copper‐Catalyzed Cross‐Coupling of Acylsilanes with Heteroarenes via Bimetallic Relay

Abstract The transition metal‐catalyzed direct coupling reactions involving electron‐rich Fischer carbene species are largely underdeveloped and remain a big challenge. Here, a direct coupling reaction of azoles and azine N‐oxides is reported with Fischer copper carbene species bearing an α‐siloxy group i, which can be in situ generated from acylsilanes catalytically under photoirradiation and redox‐neutral conditions. This coupling reaction between electron‐rich α‐siloxy Fischer Cu‐carbene species with hard carbanion nucleophiles may undergo a bimetallic relay process, which is confirmed by the kinetic analysis and in situ NMR analysis. This reaction features mild conditions and remarkable heterocycle compatibility. Notably, this protocol tolerates a series of azole or azine N‐oxide derivatives, including benzoxazole, benzothiazole, benzoimidazole, benzoisoxazole, oxazole, oxadiazole, triazolo[4,3‐a]pyridine, purine, caffeine, pyridine N‐oxide, quinoline N‐oxide, pyrazine N‐oxide, pyridazine N‐oxide, etc. The synthetic value of this approach is demonstrated by the efficient synthesis of a histamine h4 receptor ligand and a marketed drug carbinoxamine.