The iconoclastic dynamics of the 1,2,6-heptatriene rearrangement
The iconoclastic dynamics of the 1,2,6-heptatriene rearrangement
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DOI：
10.1021/ja026232a
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发表时间：
2002-07-10
影响因子：
15
通讯作者：
Borden, WT
中科院分区：
文献类型：
--
作者：
Debbert, SL;Carpenter, BK;Borden, WT
对1，2，6-庚三烯重排为3-亚甲基-1，5-己二烯的反应进行了CASSCF(8，8)/6-31G*和AM1-SRP直接动力学轨道计算。它们表明，Roth等人的实验结果。可以解释这个反应，而不需要调用协调的周环机制。相反，在反应物转化为2-亚甲基环己烷-1，4-二基的过渡态发生了分叉。一些离开过渡态的轨迹确实进入了中间体的PES局部极小值，但另一些轨迹只在实频振动模式的相位上不同，绕过中间体，继续通过第二个过渡态到达产物。尽管在CASSCF水平上的最小值约为12千卡/摩尔，但进入双自由基局部极小值的很大一部分轨迹继续进行到<；500 fS中的产物。这种非统计行为似乎部分是由于中间体中关键的C−H弯曲和C−C伸缩振动之间的共振。
CASSCF(8,8)/6-31G* and AM1-SRP direct dynamics trajectory calculations have been run on the rearrangement of 1,2,6-heptatriene to 3-methylene-1,5-hexadiene. They show that the experimental results of Roth et al. on this reaction can be explained without the need to invoke a concerted, pericyclic mechanism. Instead, bifurcation occurs at the transition state for conversion of the reactant to 2-methylenecyclohexane-1,4-diyl. Some trajectories leaving the transition state do enter the PES local minimum for the intermediate, but others, differing only in the phases of the real-frequency vibrational modes, bypass the intermediate and proceed over a second transition state to the product. A significant fraction of the trajectories that do enter the biradical local minimum proceed on to the product in <500 fs, despite the fact that the minimum is some 12 kcal/mol deep at the CASSCF level. This nonstatistical behavior seems to be due in part to a resonance between key C−H bending and C−C stretching vibrations in the intermediate.