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用密度泛函B3LYP方法研究了过渡金属钐类卡宾与乙烯的环丙烷化反应的机理。对三种不同的钐的SS试剂CH_3SmCH_2X(其中X=Cl、Br和Ⅰ)分别和CH_2CH_2反应的各反应物、中间体、过渡态和产物构型的全部结构几何参数进行了优化,用内禀反应坐标(IRC)计算和频率分析方法,对过渡态进行了验证。结果表明：CH_3SmCH_2X(其中X=Cl、Br和Ⅰ)与CH_2CH_2环丙烷化反应按亚甲基转移通道(通道A)和卡宾金属化通道(通道B)都可以进行,与锂类卡宾的反应机理相同,只是按亚甲基转移通道(通道A)进行反应较容易一些,而且此反应在较低的温度下就可以发生。
The mechanism of cyclopropanation of transition metal samarium carbene with ethylene was studied by density functional theory B3LYP method. The geometrical parameters of all structures of the reactants, intermediates, transition states and product configurations of the three different samarium SS reagents CH_3SmCH_2X (X = Cl, Br and I) and CH_2CH_2 were optimized respectively. Response Coordinate (IRC) calculation and frequency analysis method, the transition state was verified. The results show that the reaction of CH_3SmCH_2X (X = Cl, Br and I) with CH_2CH_2 cyclopropanation can be carried out by methylene transfer channel (channel A) and carbene metallization channel (channel B) In the same way, it is easier to carry out the reaction by the methylene transfer channel (channel A), and the reaction can take place at a lower temperature.