Development and Application of Orbital theory for Steric Control and Design

1.我们开发并应用了一种理论模型和方法来分析键间δ电子离域的机制。得出以下结论。(1)邻位供体-受体键的反周面排列的偏好可以归因于从插入键到受体键的种子离域以及供体和受体键之间的邻位离域。(2)孪晶δ-键之间的离域是反键，并且随着键角变窄而减小。环丙烷的稳定性出乎意料地从它的小键角不能解释的δ-芳香性，但反键孪离域的小范围内。(3)Si-Si键的δ电子离域良好。(4)P-P键具有较高的p-特征。芳香族化合物的二甲基衍生物的去质子化的选择性表明，通过键的相互作用可以控制的诱导效应，和carbaniodic中心应与芳环更强烈地比预期的相互作用。3.从头算MO计算显示了一种新的基本过程的可能性，即，四元卤离子的锯齿形塌缩，以及F_2与烯烃的合成加成反应的起源.提出了取代基效应的一个新的方面--构象适应，5-取代环戊二烯的Diels-桤木反应的π面选择性受取代基轨道能量的控制，而取代基轨道能量对反应位点前线轨道的性质有影响.第一种从π-过量的杂芳环分子中提取质子的方法被开发并应用于2-甲基吲哚的甲基的区域特异性官能化。稠合五元环杂芳异构体的相对稳定性由[6 e/6p]而不是[6 e/4p]和[6 e/5 p]共轭决定。

1. We developed and applied a theoretical model and a method for analyzing the mechanism of delocalization of delta-electrons between bonds. The following conclusions are drawn. (1) The preference of antiperiplanar arrangement of vicinal donor-acceptor bonds can be attributed to the seminal delocalization from the intervening bond to the acceptor bond as well as vicinal delocalization between the donor and acceptor bonds. (2) The delocalization between the geminal delta-bonds is antibonding and decreases as the bond angle narrows. The stability of cyclopropane unexpected from its small bond angle cannot be explained by delta-aromaticity but the small extent of the antibonding geminal delocalization. (3) delta-Electrons of Si-Si bonds delocalize well. (4) The P-P bonds have high p-character.2. Selectivities of deprotonation of dimethyl derivatives of aromatic compounds suggested that through-bond interaction could be controlled by inductive effects, and that the carbaniodic centers should interact with the aromatic rings more strongly than expected. 3. Ab initio MO calculations showed a possibility of a new elementary process, i.e., zigzag collapse of 4-membered halonium ions, and the origin of syn-addition of F_2 to olefins.4. A new aspect of substituent effects, conformational adaptation, was proposed.5 pi-facial selectivities of Diels- Alder reactions of 5-substituted cyclopentadiene are controlled by the orbital energy of the substituent, which exhibits effects on the properties of the frontier orbitals at the reaction sites.6. The first method for abstracting a proton from the pi-excessive heteroaromatic molecules were developed and applied to regiospecific functionalization of the methyl group of 2-methyindole.7. Relative stabilities of condensed 5-membered ring heteroaromatic isomers are determined by [6e/6p] rather than [6e/4p] and [6e/5p] conjugations.