An Adventure in Sustainable Cross-Coupling of Phenols and Derivatives via Carbon−Oxygen Bond Cleavage

Aryl halides are very useful electrophiles forsynthesizing various substituted aromatic compounds viametal-catalyzed cross-coupling reactions. Because of the highcost associated with their synthesis and the stoichiometrichalide waste produced when using aryl halide feedstocks,cheaper and more sustainable alternatives have been explored,such as phenols. However, phenols have a very reactivehydroxyl group and a C−O bond with high dissociationenergy. To overcome such challenges, earlier studies focusedon finding ways to reduce the energy of the C−O bond whileremoving the active proton by transforming phenols intophenol derivatives (e.g., sulfonates, esters, carbamates, ethers,and metal salts). A greater ambition is to directly cross-couplephenols with nucleophiles via C−O cleavage. In this Perspective, we briefly summarize efforts and accomplishments concerning the cross-coupling of phenol derivatives and phenol