Living cationic polymerization of dihydrofuran and its derivatives

Cationic polymerization of 2,3-dihydrofuran (DHF) and its derivatives was examined using base-stabilized initiating systems with various Lewis acids. Living cationic polymerization of DHF was achieved using Et1.5AlCl1.5 in toluene in the presence of THF at 0 °C, whereas it has been reported that only less controlled reactions occurred at 0 °C. Monomer-addition experiments of DHF and the block copolymerization with isobutyl vinyl ether demonstrated the livingness of the DHF polymerization: the number–average molecular weight of the polymers shifted higher with low polydispersity as the polymerization proceeded after the monomer addition. Furthermore, this base-stabilized cationic polymerization system allowed living polymerization of ethyl 1-propenyl ether and 4,5-dihydro-2-methylfuran at −30 and −78 °C, respectively. In the polymerization of 2,3-benzofuran, the long-lived growing species were produced at −78 °C. The obtained polymers have higher glass transition temperatures compared to poly(acyclic alkyl vinyl ether)s. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4495–4504, 2008