Effect of a chiral electrostatic cavity on product selection in a reaction with a bifurcating reaction path
Effect of a chiral electrostatic cavity on product selection in a reaction with a bifurcating reaction path
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手性静电腔对分叉反应路径反应中产物选择的影响
DOI：
10.1007/s00214-014-1525-2
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发表时间：
2014
影响因子：
1.7
通讯作者：
Carpenter B
中科院分区：
文献类型：
--
作者：
Carpenter B
探讨了在具有分叉反应路径的反应中影响产物形成分支选择的可能性。所选择的反应是众所周知的单线态环丙叉开环的取代形式。取代基的排列使得起始卡宾是内消旋的（即，非手性），但产物是对映体的联烯。所提出的问题是，是否可以通过选择在手性布置的点电荷组内发生的反应来在产物中诱导旋光性。直接动力学轨迹计算是用来解决这个问题。研究发现，在微观层次上，点电荷对分岔分支的选择有非常显著的影响。然而，当考虑到分子相对于电荷阵列的自由旋转，对各个微观效应进行平均时，净效应很小（500 fs后约3%对映体过量）。然而，即使是这个小的影响是大于人们可能已经预测的基础上，较早的分析静电贡献的手性分子之间的相互作用。原因是目前的模拟涉及手性极性物体的同心排列，而早期的分析仅考虑并排排列。通过使用数值模拟，它表明，两个自由旋转阵列的手性点电荷表现出更大的非对映体歧视时，阵列是同心的，比当他们不是，即使是可比的平均距离之间的收费。
The possibility of influencing the selection of product-forming branches in a reaction with a bifurcating reaction path is explored. The reaction chosen is a substituted version of the well-known ring opening of singlet cyclopropanylidene. The substituents are arranged such that the starting carbene is meso (i.e., achiral) but the products are enantiomeric allenes. The question being posed is whether optical activity can be induced in the products by choosing the reaction to occur within a chirally disposed set of point charges. Direct-dynamics trajectory calculations are used to address the problem. It is found that, on a microscopic level, the point charges have a very signifi cant effect on the choice of bifurcation branch. However, when the individual microscopic effects are averaged, to take account of free rotation of the molecule with respect to the charge array, the net effect is small (about 3 % enantiomeric excess after 500 fs ). Nevertheless, even this small effect is larger than one might have predicted on the basis of an earlier analysis of electrostatic contributions to the interactions between chiral molecules. The reason is that the present simulation involves a concentric arrangement of chiral, polar objects, whereas the earlier analysis considered only a side-by-side arrangement. Through the use of numerical simulation, it is shown that two freely rotating arrays of chiral point charges exhibit larger diastereomeric discrimination when the arrays are concentric than when they are not, even for comparable average distances between the charges.
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影响因子：
2.4
作者：
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DOI：
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发表时间：
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期刊：
影响因子：
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期刊：
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通讯作者：
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作者：
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影响因子：
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