Visible-Light-Induced Copper-Catalyzed Coupling Reaction of Aryl Halides with Phenols at Room Temperature

This work describes a visible-light-induced Ullmann C-O coupling between aryl halides and phenols at room temperature without an external photocatalyst. Preliminary mechanistic studies suggest that the in situ-formed LCu(I)-phenoxide complex functions as both a photosensitizer and an active catalyst. The synthetic utility of this photoinduced Ullmann-type coupling was demonstrated by a gram-scale reaction with maintained high yield and successful late-stage functionalization of pharmaceutically relevant compounds in good yields.