title: Regioselective ring-emitting esterification on azacyclohexane quaternary salts: a DFT and synthetic study for covalent fixation of electrostatic polymer self-assemblies.
abstract: A regioselective nucleophilic esterification upon six-membered, thus considered unstrained, azacyclohexane quaternary salts has been disclosed by DFT calculations using a model compound and subsequent experimental studies of nucleophilic substitution on N-phenyl-3,3-dimethylpiperidinium salt groups at the polymer chain ends by carboxylate anions. An exclusive ring-emitting esterification was proposed theoretically and confirmed experimentally to produce a simple ester group, in contrast to less robust amino-ester linkages through an alternative ring-opening process with strained five-membered ammonium salts. This reaction was subsequently applied to a prototypical process of an electrostatic self-assembly and covalent fixation (ESA-CF) technique to produce a ring polymer having simple ester linking units.
authors.affiliation: Department of Organic and Polymeric Materials, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Kimura
authors.forename: Shinnosuke
authors.initials: S
authors.lastname: Takahashi
authors.forename: Susumu
authors.initials: S
authors.lastname: Kawauchi
authors.forename: Takuya
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Tezuka
mesh_terms: D001372:Aza Compounds / Q000737:chemistry*; D003510:Cyclohexanes / Q000737:chemistry*; D004952:Esters / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D011789:Quantum Theory; D012492:Salts / Q000737:chemistry; D055672:Static Electricity; D013237:Stereoisomerism
chemical_list: D001372:Aza Compounds; D003510:Cyclohexanes; D004952:Esters; D011108:Polymers; D012492:Salts; C506365:Cyclohexane