Selective Modular Synthesis of <i>ortho</i>-Substituted Phenols via Pd-Catalyzed Dehydrogenation–Coupling–Aromatization of Alcohols

Abstract

Phenols are pivotal precursors and core motifs for various fine chemicals, bioactive molecules, and functional materials, among which the site-selective syntheses of ortho-substituted phenols are very attractive and challenging. Here, we present a palladium-catalyzed dehydrogenation–coupling–aromatization protocol to access ortho-substituted phenols from cyclohexanols with primary alcohols. Broad substrate scope was achieved in this modular protocol with water and hydrogen gas as clean byproducts. The ortho-mono- and ortho-disubstitutions were readily controlled by N-heterocyclic carbene (NHC) ligands and the amount of base.