Positional chemoselectivity in the Zn(II)-mediated removal of phenol protecting groups

A protocol was developed for the chemoselective ortho-deprotection of polyphenolic substrates using readily available ZnIIX2 salts. This procedure provides exceptional positional selectivity for the deprotection of phenols that reside adjacent to directing carbonyl functionality in the presence of similar protecting groups at the meta and para positions. Good to excellent yields of the desired free phenols were obtained (⩽96%), and a wide assortment of protecting groups was readily removed under the reaction conditions.