Synthesis of Cleavable Polymers via Oxidation of Thioether Moieties and Thiol Click Reactions: A Click-Declick Strategy.

Abstract

In the past decades click chemistries including thiol chemistries have found wide applications in the synthesis of well-defined polymers. In this research, a click-declick strategy based on the oxidation of heteroaromatic thioethers and the substitution reactions between the oxidized groups and thiols, is proposed for the synthesis of the cleavable polymers. In proof-of-concept experiments, block copolymers (BCPs) and star-like polymers are synthesized by thiol-phenylsulfone substitution reactions, and heteroaromatic thioethers are produced at the junction points of the BCP chains or on the crosslinking sites of the star-like polymer. The thioethers can be oxidized to heteroaromatic sulfoxides or sulfones, depending on the oxidization condition. It is demonstrated that both sulfoxides or sulfones can have base catalyzed nucleophilic substitution reactions with thiols, leading to the cleavage of the polymers.