Theoretical Studies of the Electrocyclic Reaction Mechanisms of o-Xylylene to Benzocyclobutene
Theoretical Studies of the Electrocyclic Reaction Mechanisms of o-Xylylene to Benzocyclobutene
复制标题
邻二甲苯制苯并环丁烯电环反应机理的理论研究
DOI：
10.1021/jp0024017
复制
发表时间：
2000
影响因子：
2.9
通讯作者：
S. Sakai
中科院分区：
文献类型：
--
作者：
S. Sakai
用从头算分子轨道方法计算了邻苯二甲撑与苯并环丁烯电环化反应的势能面。得到了邻二甲苯电环化反应顺旋和反旋两种反应途径的过渡态。顺旋和反旋路径上的能垒差异非常小：7.4 kcal/mol（由完全活性空间自洽场（CASSCF）计算确定）和8.0 kcal/mol（由完全活性空间二阶Moller-Plesset微扰（CAS-MP2）计算确定）。还估计了由于轨道相位（如轨道对称规则）引起的能量差：在CAS-MP2计算中为3.5 kcal/mol。通过构型相互作用（CI）-局域分子轨道（LMO）-CASSCF沿着内禀坐标（IRC）途径（CiLC-IRC）方法分析了这些沿着顺旋和反旋反应途径的机理。
The potential energy surfaces for the electrocyclic reactions of o-xylylene to benzocyclobutene were calculated by ab initio molecular orbital methods. The transition states of two reaction pathways, conrotatory and disrotatory, for the electrocyclic reaction of o-xylylene were obtained. The difference of energy barriers on the conrotatory and the disrotatory pathways is extremely low: 7.4 kcal/mol as determined by complete active space self-consistent field (CASSCF) calculations and 8.0 kcal/mol as determined by complete active space second-order Moller-Plesset perturbation (CAS−MP2) calculations. The energy difference due to the orbital phase such as the orbital symmetry rules was also estimated: 3.5 kcal/mol at the CAS-MP2 calculations. These mechanisms along the conrotatory and the disrotatory reaction pathways were analyzed by the configuration interaction (CI)−localized molecular orbital (LMO)−CASSCF along the intrinsic coordinate (IRC) pathway (CiLC−IRC) method.