Regioselective Ring-Emitting Esterification on Azacyclohexane Quaternary Salts: A DFT and Synthetic Study for Covalent Fixation of Electrostatic Polymer Self-Assemblies

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• 作者：Akihiro Kimura ; Shinnosuke Takahashi ; Susumu Kawauchi ; Takuya Yamamoto ; Yasuyuki Tezuka
• 刊名：The Journal of Organic Chemistry
• 出版年：2013
• 出版时间：April 5, 2013
• 年：2013
• 卷：78
• 期：7
• 页码：3086-3094
• 全文大小：490K
• 年卷期：v.78,no.7(April 5, 2013)
• ISSN：1520-6904

文摘

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.