Development of New Method for Preparation of Heterocycles Using Reactive Intermediates.

众所周知，乙烯基阳离子是通过亲电加成形成的反应中间体之一。我们还发现，乙烯基卤化物的光解和溶剂分解产生乙烯基阳离子。在这项研究中，我们研究了通过分子内反应形成杂环，其中乙烯基阳离子在阳离子中心的相邻位置含有杂原子，如氧和硫。结果表明，所得环鎓离子的环状结构和杂原子的性质在稳定性和分离方面起着重要作用。特别是在硫的情况下，分离的环状锍离子的光谱数据和化学行为表明硫的结构.乙烯基叠氮化合物通过乙烯基卤化物的亲核取代反应，热或光化学得到氮杂环丙烷，其在热条件下发生C-N裂变，生成乙烯基氮烯.乙烯基氮烯的电环化反应提供5、6和7元杂环。特别是通过氮杂环丙烷二聚反应得到的吡嗪衍生物显示出液晶性质，在分子组装化学中有着重要的应用。制备了各种含杂环液晶和两亲性化合物。这些化合物形成单分子膜。在实验和理论结果的基础上讨论了单分子膜的结构与行为之间的关系。本研究制备的LB膜具有很强的SH强度，有望发展为光学材料。

It is well known that vinyl cations, one of reactive intermediates, are formed by electrophilic addition to acetylenic bonds. We have also found that photolysis and solvolysis of vinyl halides generate vinyl cations. In this study we investigated formation of heterocycles by intramolecular reaction, in which vinyl cations contain heteroatoms such as oxygen and sulfur at the neighboring position to the cationic center. The results indicated the cyclic structure of the resulting cyclic onium ions and the nature of the heteroatom play a significant role in the stability and the isolation. In particular, in the case of sulfur, the spectral data of the isolated cyclic sulphonium ion and the chemical behaviors suggested the sulphurane structure.Vinyl azides obtained by nucleophilic substitution of vinyl halides afford azirines thermally or photochemically, which undergo C-N fission in thermolysis to produce vinyl nitrenes. the electrocyclic reaction of vinyl nitrenes provides 5, 6, and 7-membered heterocycles. Especially, pyrazine derivatives obtained by dimerization of azirines showed the character of liquid crystals and werre applied to chemistry of molecular assembly. Various heterocycle-containing liquid crystals and amphiphilic compounds were prepared. These compounds formed monolayers. The relationship between the behavior and the structure of the monolayers were considered on the empirical and theoretical results. The LB films prepared by this study showed a large SH intensity and were developed to optical materials.