Visible-Light-Induced Ru-Catalyzed Ortho C−H Diarylation of 2-Phenyl-2H-Indazoles and 1-Phenyl-1H-Pyrazoles

Abstract C–H functionalization is unlocking new avenues in molecular design by transforming the inert carbon–hydrogen bond into a versatile handle for creating complex and value-added compounds with remarkable precision. Taking this into account, we have developed a new ruthenium-catalyzed mild, one-step, robust methodology for ortho C−H diarylation of 2-phenyl-2H-indazoles using aryl iodides as an arylating reagent under photo-mediated conditions at room temperature. This approach extends seamlessly to another heteroarene, 1-phenyl-1H-pyrazole. The strategy shows broad substrate scope, an extensive range of functional group compatibility, and moderate to excellent yield formation. Furthermore, gram-scale synthesis demonstrates the practical applicability of the method.