Dehydrogenative Aromatization of Cyclohexanone Derivatives for the Synthesis of Site-selective Substituted Phenols and Anilines

Abstract

Aromatic compounds containing phenol or aniline functionalities are ubiquitous building blocks in various fields both in academic and industrial chemistry. Traditionally, substituted phenols and anilines are synthesized via electrophilic or nucleophilic aromatic substitution, but the regioselectivity is constrained by the substituents. The dehydrogenative aromatization of cyclohexanone derivatives, as an alternative, has a transformative influence on the synthesis of phenol or aniline derivatives that can overcome the limitation of ortho-, meta-, or para-orientations. This review mainly focuses on the recent research progress since 2020 concerning the two types of dehydrogenative aromatization: oxidative and acceptorless, in synthesizing substituted phenols and anilines. Representative examples are examined and classified by catalysis patterns. The associated reaction mechanisms and applications are also included, which offers a comprehensive and up-to-date overview of these compounds for synthesis purposes.