Deprotection of pinacolyl boronate esters by transesterification with polystyrene-boronic acid

Abstract

A mild, efficient method for the deprotection of pinacolyl organoboronate esters is described. Treatment of the organoboronate ester with excess polystyrene-boronic acid followed by filtration and evaporation of the solvent provides the corresponding organoboronic acid. Mild deprotection of pinacolyl boronate esters to the corresponding boronic acids was achieved in the presence of excess polystyrene-boronic acid via a transesterification process. The procedure allows for the cleavage of pinacolyl boronate esters in the presence of sensitive functional groups. Crown Copyright © 2004 Published by Elsevier Ltd. All rights reserved.