Reaction control of cyclic ethers by new versatile catalysts and its application

环氧乙烷与异氰酸酯、碳二亚胺等杂立方烯的环加成反应一直是人们研究的热点。尽管已经报道了多种催化剂用于该反应，但反应条件苛刻、产率低等问题仍未得到解决。现在，我们的项目在开发新型催化剂方面给出了一个解决方案：有机锡碘-Lewis碱配合物(1)、有机锡碘-碘卤化盐络合物(2)和四苯基碘化锡(3)。这些催化剂非常有效地促进了环加成反应，在非常温和的条件下以极高的产率合成了多种杂环化合物。这些催化剂的优点和特点如下：(a-c)；(A)在室温下几小时内完成环加成反应；(B)催化剂1和2选择性地促进单取代环氧烷的-裂解环加成反应。相反，催化剂3促进了传统催化剂根本不成功的-解离反应。对于相同的反应物，这两种反应都可以在相似的反应条件下进行，因此这些催化剂可以补偿使用。(C)这些催化剂是近中性的，所以含有不稳定取代基的氧杂环适合于这种环加成反应。

The cycloaddition of oxiranes with heterocumulenes such as isocyanates and carbodiimides has been ardently investigated. Although a variety of catalysts for this reaction have been reported, the problems such as low yields and severe reaction conditions have not been resolved as yet. Now, this our project has given one resolution in terms of developing novel catalysts; organotin iodide-Lewis base complexes(1), organotin iodide-onium halide salts complexes(2) and tetraphenylstibonium iodide(3). These catalysts very effectively promoted the cycloadditon of under very mild conditions to produce many kinds of heterocyclic compounds in excellent yield. Advantages and features of these catalysts are as follows(a-c);(a) The cycloadditions complete within few hours at room temperature.(b) The catalysts 1 and 2 selectively promote the -cleavage cycloaddition of monosubstituted oxiranes. On the contrary, the catalyst 3 promotes the -cleavage one which has been unsuccessful by conventional catalysts at all. The both reactions could be carried out for the same reactants under similar reaction conditions, and so these catalysts can be used compensationally.(c) These catalysts are so nearly neutral that the oxiranes bearing labile substituents are applicable to this cycloaddition.