Development and Application of Orbital theory for Steric Control and Design

点击翻译按钮获取中文摘要

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.