高等学校化学学报

高等学校化学学报 ›› 2002, Vol. 23 ›› Issue (1): 109.

• 研究论文 • 上一篇    下一篇

不对称硼催化反应的理论研究(Ⅰ)——噁唑硼烷催化苯基乙酮还原反应的对映体选择性机理

孙成科1,2, 杨思娅2, 马思渝1, 李宗和1   

  1. 1. 北京师范大学化学系, 北京 100875;
    2. 曲靖师范学院, 曲靖 655000
  • 收稿日期:2000-10-18 出版日期:2002-01-24 发布日期:2002-01-24
  • 通讯作者: 孙成科(1958年生),男,教授,从事化学反应机理研究.E-mail:cksun@qjnc.edu.cn E-mail:cksun@qjnc.edu.cn
  • 基金资助:

    国家自然科学基金(批准号:29773007);云南省教委科学研究基金(批准号:001224)资助

Theoretical Studies on Asymmetric Boron-catalyzed Reaction(Ⅰ) The Enantioselectivity in Oxazaborolidine-catalyzed Reductions of Phenyl Ethyl Ketone

SUN Cheng-Ke1,2, YANG Si-Ya2, MA Si-Yu1, LI Zong-He1   

  1. 1. Department of Chemistry, Beijing Normal University, Beijing 100875, China;
    2. Department of Chemistry, Qujing Normal College, Qujing 655000, China
  • Received:2000-10-18 Online:2002-01-24 Published:2002-01-24

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摘要： 用AM1方法研究了噁唑硼烷催化苯基乙酮还原反应的对映体选择性机理,结果表明,在此硼催化剂的作用下,苯基乙酮还原的对映体产物主要是R构型,其主要原因是两种对映体的催化过渡态的活化能相差较大所致.用过渡态活化理论计算所得光学产率e.e.=95%,计算结果与实验一致.

关键词: 苯基乙酮, 硼催化, 对映体选择性, AM1

Abstract: The reaction mechanism of the enantioselectivity in oxazaborolidine catalyzed reductions of phenyl ethyl ketone has been studied by using AM1 method and transition state theory. The results show that the boron-catalyzed reactions consist of two similar parallel reactions in which the reactants(R) of the title compound and boron catalyst generate the enantiomers(PR and PS) via intermediate compounds IC(R) and IC(S) and transition states TSR and TSS, respectively. The enantioselectivity is determined by the ratio of the rate constants of two reactions. The value is 40 (that is R:S =97.5:2.5 or e.e. (R) =95%), which is in good consistence with experiment [exp. e.e. (R) =97(95)%]. The determining factors of the rate ratio come from the joint contribution of the activation enthalpy and activation entropy.

Key words: Phenyl ethyl ketone, Boron catalyzed, Enantioselectivity, AM1

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