(C₆F₅)₃B Catalyzed Chemoselective and ortho-Selective Substitution of Phenols with α-Aryl α-Diazoesters

The development of an efficient method for the site-selective substitution of unprotected phenols has long been considered as an attractive but challenging task. Herein, we describe a highly chemo- and ortho-selective substitution reaction of phenols with α-aryl α-diazoacetates with commercially available (C₆F₅)₃B as the catalyst. This reaction proceeds under simple and mild conditions with high efficiency, it features a wide substrate scope and can be easily scaled up.