ABC-Type Periodic Terpolymer Synthesis by a One-Pot Approach Consisting of Oxirane- and Carbonyl-Derived Cyclic Acetal Generation and Subsequent Living Cationic Alternating Copolymerization with a Vinyl Monomer

A one-pot synthesis of ABC-type periodic terpolymers with controllable molecular weights was achieved via an elaborately designed method consisting of sequence-programmed cyclic monomer synthesis and living cationic copolymerization of this cyclic monomer with a vinyl monomer. In this method, a cyclic acetal generated by a selective and quantitative Lewis acid-catalyzed cyclodimerization reaction of an oxirane and a carbonyl compound was subjected to subsequent copolymerization without any isolation or purification. Alternating copolymerization of the cyclic acetal and vinyl ether (VE) proceeded, yielding an ABC-type periodic terpolymer composed of oxirane, a carbonyl compound, and VE. Interestingly, the copolymerization proceeded in a living manner, which allowed simultaneous control of the molecular weight, molecular weight distribution, and chain ends in addition to the periodic sequence. Moreover, the terpolymers could be degraded by acid due to the periodically located acetal moieties. The use of various monomers also produced ABC-type sequence terpolymers. ABC- b -ABD-type periodic block quaterpolymers were synthesized by the sequential addition of vinyl monomers during the living copolymerization. These results surely provide a simple and efficient approach for the design of monomer sequences, polymer lengths, and chain ends in synthetic polymers.