Carbazole-Based Catalysts as a Versatile Platform for Halogen-Bonding and Photoredox Catalysis

This report describes an electron-rich carbazole catalyst for the photogeneration of radicals from a range of alkyl halides. Mechanistic studies showed that two distinct catalytic pathways could be accessed, with the carbazole capable of serving as an effective photoredox catalyst under direct irradiation or as a halogen-bonding photocatalyst in the presence of suitable halogen-bond donors. Both strategies enabled radical alkylation reactions with comparable efficiencies, providing alternative options depending on the desired starting substrate and irradiation wavelength.