Design of the Molecules Bearing Specific Stereochemistry and Its Application to the Development of New Reactions

本文利用动态<@D111 @> D1 H-和<@D113@>D1C-NMR、<@D1119@> D1 Sn-NMR和X射线分析，对具有烷氧基和硅氧基取代基的六元环化合物进行了构象分析。因此，这是明确的，椅型3-甲硅烷基氧基取代的戊二酸酐和戊二酰亚胺和椅型环己酮具有烷氧基或甲硅烷基氧基基团在C4位置可以占主导地位，采取各自相应的取代基轴向构象在其溶液中。在动态<@D11@> D1 H-NMR谱上，发现椅型硫杂环丁烷-1-氧化物、硫杂环丁烷-1，1-二氧化物和二氢硫杂环丁烷的C4位上的硅氧基和苄氧基具有类似的轴向或拟轴向优先性。在一些六元化合物的晶体结构中也观察到烷氧基和硅氧基的轴向选择性。存在吸电子部分（（）SY. [)C=O，（]SY. [)SO，（]SY. [)SO<@D22@>D2）和低碱度的硅氧和烷氧基氧原子被证明是采用轴向构象的必要条件，这可以用一般假设来合理化;由于C3，5-Hsigma，C4-Osigma<@D1*@>D1轨道重叠而使轴向构象稳定。几种分子，采用与两种芳族化合物如三唑和苯衍生物堆叠的弯曲构象，已经开发并通过X射线晶体学和^1H-NMR分析表征。用磺酸酯键桥接两个芳族部分似乎是弯曲构象的重要因素。在分子力学计算的基础上，设计和合成了具有独特S形构象的新分子。

We are extensively developing a new system in which stereochemistry and reaction of the unique molecule can be regulated under the electronic control.Conformational analysis of various six-membered ring compounds possessing alkoxy and silyloxy substituents has been performed by utilizing their dynamic <@D11@>D1H- and <@D113@>D1C-NMR, <@D1119@>D1Sn-NMR, and X-ray analyses. Thus, it was clarified that chair-type 3-silyloxy-substituted glutaric anhydride and glutarimide and the chair-type cyclohexanones possessing alkoxy or silyloxy group at the C4 position can predominantly adopt each corresponding substituent-axial conformer in their solution. Similar axial or pseudoaxial preference of silyloxy and benzyloxy groups at C4 of chair-type thiane-1-oxides, thiane-1, 1-dioxides, and dihydrothiines was recognized on their dynamic <@D11@>D1H-NMR spectra. Such axial preference of alkoxy and silyloxy groups of several six-membered compounds was also observed in their crystallographic structures. Existence of the electron-withdrawing moiety ((]SY.di-substituted left.[)C=O, (]SY.di-substituted left.[)SO, (]SY.di-substituted left.[)SO<@D22@>D2) and the low basicity of silyloxy- and alkoxy-oxygen atom proved to be essential for adopting the axial conformer, which could be rationalized in terms of a general hypothesis ; stabilization of the axial conformer due to C3, 5-Hsigma, C4-Osigma<@D1*@>D1 orbital overlap.Several molecules, adopting a bent conformation stacked with both aromatics such as triazoles and benzene derivatives, have been developed and characterized by X-ray crystallographic and ^1H-NMR analyses. Bridging both aromatic moieties with a sulfonic ester bond seems to be an essential factor for the bent conformation. Design and synthesis of new molecules adopting a unique sigmoid conformation have been achieved on the basis of a molecular mechanic calculation.