Accessing para-Alkylphenols via Iridium-Catalyzed Site-Specific Deoxygenation of Alcohols

J Org Chem. 2023 Sep 1;88(17):12572-12584. doi: 10.1021/acs.joc.3c01294. Epub 2023 Aug 18.

Abstract

An iridium-catalyzed and phenol-directed deoxygenation of benzylic alcohols comes as an alternative access to 4-alkylphenols, featuring low catalyst loading (S/C up to 20,000, TOF up to 12,400 h-1), high functionality compatibility, and excellent site-selectivity. The applications in late-stage modification of steroids and gram-scale total synthesis of a Gastrodia elata extract are highlighted. Mechanistically, the intermediacy of quinone methide controls the site-selectivity, and the formation of iridium hydride serves as the rate-limiting step.