Biaryl Synthesis via C–H Bond Activation: Strategies and Methods

The biaryl unit is a recurrent building block in numerous compounds that have profoundly changed many aspects of the modern era. As a structural component in drugs, agrochemicals, and materials, the biaryl moiety is a highly desirable synthetic target for both industry and academia. In recent years, transition metal-catalyzed C–H arylation methodologies for the construction of the biaryl skeleton have been acknowledged as a sustainable alternative to traditional cross-coupling reactions. The aim of this review is to offer a general overview on the most successful strategies for the formation of C_Ar–C_Ar bonds in this rapidly evolving field. Particular emphasis on the mechanistic implications governing both selectivity and reactivity will be provided, where appropriate.