醚溶液中烯烃硼氢化反应机理的理论模拟  

A Theoretical Simulation of Hydroboration of Alkenes with BH_3 in Ether Media

作　　者：范育波[1] 丁宗彪[1] 王全瑞[1] 陶凤岗[1] 

机构地区：[1]复旦大学化学系,上海200433

出　　处：《高等学校化学学报》2001年第8期1364-1367,共4页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金 (批准号 :2 9872 0 0 7)

摘　　要：在 B3LYP/6-31 G* 水平上以二甲醚 ( Me2 O)模拟四氢呋喃 ( THF)对烯烃在 THF溶液中硼氢化反应的机理进行了研究 .计算结果发现 ,烯烃通过类似 SN2的交换过程从醚与 BH3构成的配合物获得 BH3结合成π配合物中间体 。The reaction of the monomeric BH 3 with alkenes in ether media has been examined by using B3LYP, a hybrid density functional method, with 6 31G * basis set. Calculations of various possible species involved in the hydroboration process, including the complexes of borane (BH 3) with dimethyl ether, ethylene, propene, 1 butene, trans 2 butene, cis 2 butene, 2 methylpropene, 2 methyl 2 butene and 2,3 dimethyl 2 butene as well as the reactants and transition states of the corresponding hydroboration have been performed. The zero point energies(ZPE) and thermal analyses were computed at the same level. Based on the calculations, the prior formation of a three center π complex intermediate of BH 3 with the respective alkene is predicted and the overall reaction rate was determined. For the formation of the π complex intermediates, two extreme pathways, i.e . the S N1 and S N2 like manner, have been compared, with the latter one more preferentially in terms of the activation barrier by 25~28 kJ/mol endothermically.

关 键 词：硼氢化反应 烃烯 密度泛函理论 醚溶液 催化作用 反应机理 

分 类 号：O623.121[理学—有机化学] O643.32[理学—化学]