title: A Rational Entry to Cyclic Polymers via Selective Cyclization by Self-Assembly and Topology Transformation of Linear Polymers.
abstract: A simple and effective synthetic route to cyclic polymers has been developed based on the following sequence: (i) selective cyclization of two self-complementary sec-ammonium-containing crown ether monomers to afford [c2] daisy-chain bifunctional initiators, (ii) living polymerization to afford the corresponding linear polymers, and (iii) a topology transformation of these linear polymers to furnish cyclic polymers. The key step in this sequence is the quantitative cyclization via self-assembly of two crown ether molecules with hydroxyl and sec-ammonium moieties. After the living polymerization, the linear polymers release the daisy-chain assembly to generate a cyclic topology. The specific advantages of the present synthetic protocol, i.e., procedural simplicity and concentration independence, are demonstrated by a gram-scale synthesis.
authors.affiliation: Department of Chemical Science and Engineering, Tokyo Institute of Technology and ‡JST-CREST, Ookayama, Meguro, Tokyo 152-8552, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Aoki
authors.affiliation: Department of Chemical Science and Engineering, Tokyo Institute of Technology and ‡JST-CREST, Ookayama, Meguro, Tokyo 152-8552, Japan.
authors.forename: Gouta
authors.initials: G
authors.lastname: Aibara
authors.affiliation: Department of Chemical Science and Engineering, Tokyo Institute of Technology and ‡JST-CREST, Ookayama, Meguro, Tokyo 152-8552, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Uchida
authors.affiliation: Department of Chemical Science and Engineering, Tokyo Institute of Technology and ‡JST-CREST, Ookayama, Meguro, Tokyo 152-8552, Japan.
authors.forename: Toshikazu
authors.identifier: 0000-0002-4601-3443
authors.initials: T
authors.lastname: Takata