Polystyrylboronic acid: A new polymeric protecting group for the selective functionalization of polyols.

Abstract

A regenerable polystyrylboronic acid resin has been prepared for the selective functionalization of polyols. The resin reacts with a diol group of a polyol to form a resin-bound cyclic boronate. Both the coupling and cleavage steps are performed under very mild conditions (removal or addition of water) and the resin is regenerated directly by the cleavage step. Monoacyl derivatives of some acyclic polyols and some partially acylated carbohydrate derivatives have been prepared efficiently on the resin without the need for any purification of intermediates. In addition, the polystyrylboronic acid resin which exhibits a high selectivity for cis diol systems, can be used in the separation of cis and trans diol mixtures such as the cyclohexanediols by affinity chromatography.