キラルジオールをテンプレートとした不斉ラジカル環化共重合における主鎖不斉ポリマーの生成機構  [in Japanese] Synthesis of Main Chain Chiral Polymer via Asymmetric Radical Cyclocopolymerization using a Chiral Diol as a Template  [in Japanese]

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Author(s)

Abstract

The cyclocopolymerization of bis (4-vinylbenzoate) (1) of a chiral diol with styrene has been studied in order to clarify the relationship between chiral template structure and its chirality inductivity. The polymerization was carried out using AIBN as an initiator in dry toluene ([1+styrene] <SUB>0</SUB> = 0.1 mol·L<SUP>-1</SUP>) at 60°C. After removal of the chiral template from the resulting polymer 2, the template-free polymer, i.e., poly [(methyl 4-vinylbenzoate) -<I>co</I>-styrene] (3), showed optical activity, which significantly depended on the chiral template used. When the optically active polymer 3 was obtained, the specific rotations ([α] <SUB>435</SUB>) of the polymer increased with a decrease in the mole fraction of methyl 4-vinylbenzoate unit in the polymer, indicating that the optical activity was attributable to the isolated benzoate diad. According to the exciton chirality method, the CD spectra of polymers 3 indicated that the dextrorotatory polymer 3 had a higher content of (<I>S</I>, <I>S</I>) -racemo benzoate diad over (<I>R</I>, <I>R</I>) -racemo one and the levorotatory polymer 3 was in the reverse situation. The stereoselection was also observed in the radical cyclization using an organotin compounds as a chain transfer reagent. In addition, the stereoisomer distribution of the resulting cyclized unimers indicated that the chiral template inhibited the formation of the unfavorable racemo diad in four possible diads. The calculated heat of formation of cyclized radical by means of semiempirical MO calculation supported the experimental results and gave a model for chirality induction.

Journal

  • Journal of Synthetic Organic Chemistry, Japan

    Journal of Synthetic Organic Chemistry, Japan 58(4), 306-315, 2000-04-01

    The Society of Synthetic Organic Chemistry, Japan

References:  38

Codes

  • NII Article ID (NAID)
    10008819749
  • NII NACSIS-CAT ID (NCID)
    AN0024521X
  • Text Lang
    JPN
  • Article Type
    ART
  • ISSN
    00379980
  • NDL Article ID
    5342104
  • NDL Source Classification
    ZP11(科学技術--化学・化学工業--有機化学・有機化学工業)
  • NDL Call No.
    Z17-256
  • Data Source
    CJP  NDL  J-STAGE 
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