PALLADIUM-CATALYZED INSERTION OF ISOCYANIDES INTO THE SILICON-SILICON LINKAGES OF OLIGOSILANES
PALLADIUM-CATALYZED INSERTION OF ISOCYANIDES INTO THE SILICON-SILICON LINKAGES OF OLIGOSILANES
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DOI：
10.1021/ja00023a043
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发表时间：
1991-11-06
影响因子：
15
通讯作者：
MURAKAMI, M
中科院分区：
文献类型：
--
作者：
ITO, Y;SUGINOME, M;MURAKAMI, M
详细介绍了钯催化剂促进低聚硅烷与异氰酸酯反应的研究。在醋酸钯的存在下加热低聚硅烷和过量2,6-二取代芳基异氰化物的混合物，导致异氰化物完全插入到所有硅-硅键中，得到低聚（硅亚胺）衍生物。到目前为止，在低聚硅烷直至六硅烷的完全插入反应中已经分离并表征了低聚（硅胺）。使用限量的异氰化物允许异氰化物主要插入到末端硅-硅键中。插入反应的方式取决于硅上的取代基，例如，内部硅原子上有苯基的四硅烷有利于在末端硅-硅键处进行插入反应，导致部分插入。芳香异氰化物上邻位取代基的体积也对插入有很大影响；因此2,6-二异丙基苯基异氰化物有利于部分插入。在钯催化下，取代芳基异氰化物与四、六硅烷发生骨架重排，生成3,3-双（硅基）-l-氮杂- 2,4 -二硅环丁烷衍生物。这种重排是独特而有趣的，因为它是由四硅烷的四个片段和异氰化物的两个片段正确地重组而成的，在叔烷基异氰化物的存在下促进了重排。
Full details of a study on the reactions of oligosilanes with isocyanides promoted by a palladium catalyst are described. Heating a mixture of oligosilanes and excess 2,6-disubstituted aryl isocyanide in the presence of palladium(II) acetate led to the complete insertion of isocyanide into all silicon-silicon linkages, giving oligo(silylimine) derivatives. The oligo(silylimine)s have been isolated and characterized so far in the complete insertion reaction with oligosilanes up to a hexasilane. Use of the limiting amount of isocyanide permitted insertion of isocyanide into predominantly the terminal silicon-silicon linkages. The mode of the insertion reaction depends on the substituent at the silicon, e.g., tetrasilanes with phenyl groups on the internal silicon atoms favorably underwent the insertion reaction at the terminal silicon-silicon linkages, resulting in the partial insertion. The bulkiness of the ortho substituents on the aromatic isocyanide was also found to have much influence on the insertion; hence, 2,6-diisopropylphenyl isocyanide favored the partial insertion. New skeletal rearrangement of oligosilanes took place in a palladium-catalyzed reaction of substituted aryl isocyanide with tetra- and hexasilanes, forming 3,3-bis(silyl)-l-aza-2, 4-disilacyclobutane derivatives. The rearrangement, which is unique and intriguing in that the product is properly reconstituted from four fragments of the tetrasilane and two fragments of the isocyanide, was promoted in the copresence of a tert-alkyl isocyanide.