New acyl-group transfer polymerization of thiiranes using carboxylic acid derivatives and quaternary onium salts

A new acyl-group transfer polymerization of thiiranes using carboxylic acid derivatives and quaternary onium sails was investigated. 3-Phenoxypropylene sulfide (PPS) was polymerized efficiently by S-phenyl thioacetate in the presence of tetrabutylammonium chloride, bromide, or tetrabutylphosphonium chloride to give the corresponding polysulfide with a S-acetyl group at the polymer terminal. The polymerization of 3-butoxypropylene sulfide (BPS) and cyclohexene sulfide (CHS) also proceeded under the similar conditions to afford the corresponding polymers. It was found from the polymer structures and results of post-polymerization that the polymerization proceeded transferring an acyl group in each propagating step. It was demonstrated that the acyl-group transfer polymerization has living nature. Furthermore, di- and tri-block copolymers of a variety of thiiranes were successfully synthesized by the present acyl-group transfer polymerization.