噁唑硼烷催化还原二苯基已二酮的反应机理研究  

Theoretical Study on Reaction Mechanism in Oxazaborolidine-Catalyzed Reductions of Diphenyl Diketohexane

作　　者：林雪飞[1] 孙成科[1] 杨思娅[1] 

机构地区：[1]曲靖师范学院化学系,云南曲靖655000

出　　处：《曲靖师范学院学报》2002年第3期42-46,共5页Journal of Qujing Normal University

基　　金：云南省教委科研基金资助项目 (0 12 2 4);曲靖师院科研基金资助项目 (2 0 0 0 0 9)

摘　　要：本文用量子化学AM1方法研究了二苯基已二酮在唑硼烷催化还原下的对映体选择性反应机理 ,结果表明 ,在此硼催化剂的作用下 ,二苯基已二酮的还原对映体产物主要是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 .=99.7。The reaction mechanism of the enantioselectivity in oxazaborolidine-catalyzed reductions of diphenyl diketohexane has been studied with the molecular orbital 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(P R and Ps)via intermendiate compounds IC(R) and IC(S) and transition states TS R and TS s respectively.The enantioselectivity is determined by the ratio of the rate constants of two reactions.The value is 615(that is R:S=99 85:0 15 or %ee(R)=99 7),that is in good consistence with experiment [exp.%ee(R)=99].The determining factors of the rate ratio come from the joint contribution of the activation entyalpy and activation entropy.

关 键 词：二苯基己二酮 硼催化剂 对映体选择性 量子化学 AMI方法 恶唑硼烷 催化还原 

分 类 号：O625.42[理学—有机化学] O621.254.3[理学—化学]