Phenol-Directed C–H Functionalization

Phenols are important starting materials, intermediates, and functional elements of a very broad range of chemicals and materials. They are large-volume products of benzene oxidation and are increasingly available from biomass. Investment in methodologies that improve the efficiency of their use can have both immediate and future impacts on chemical upgrading. This review summarizes recent phenol-directed C–H functionalization reactions, which provide efficient increases in molecular complexity. Catalytic methodologies play an increasingly important role in addressing long-standing challenges of chemo- and regioselectivity, setting the stage for increased use of phenols in fine-chemical synthesis. We discuss these advances while underscoring persistent challenges, with the goal of motivating increased interest in this versatile functional group.