A heavy analogue of the smallest bridgehead alkene stabilized by a base
A heavy analogue of the smallest bridgehead alkene stabilized by a base
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由碱稳定的最小桥头烯烃的重类似物
DOI：
10.1038/ncomms6353
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Shintaro Ishida
中科院分区：
文献类型：
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作者：
Takeaki Iwamoto;Naohiko Akasaka;Shintaro Ishida
双环[1.1.0]丁-1（2）-烯（BBE）是一种最小的桥头烯烃和C_4H_4异构体，理论上作为反应中间体存在，但实验上尚未观察到。在这里，我们成功地合成了BBE的硅类似物，四硅双环[1.1.0]丁-1（2）-烯（Si 4 BBE），在碱稳定的形式。X射线衍射分析和理论研究结果表明，Si 4 BBE主要以四硅高环丙烯鎓阳离子和硅阴离子的两性离子结构存在，而不是具有局部高张力双键的双环结构.碱稳定的Si 4 BBE与三苯基硼烷反应得到Si 4 BBE的[2+2]环加合物和Si 4 BBE的异构体四硅双环[1.1.0]丁-2-亚基（Si 4 BBY）的二聚体。理论计算和捕集反应支持了Si_4BBE和Si_4BBY之间的易异构化反应。公开了最小桥头烯烃的重质类似物的结构和性质。
Bicyclo[1.1.0]but-1(2)-ene (BBE), one of the smallest bridgehead alkenes and C4H4isomers, exists theoretically as a reactive intermediate, but has not been observed experimentally. Here we successfully synthesize the silicon analogue of BBE,tetrasilabicyclo[1.1.0]but-1(2)-ene (Si4BBE), in a base-stabilized form. The results of X-ray diffraction analysis and theoretical study indicate that Si4BBE predominantly exists as a zwitterionic structure involving atetrasilahomocyclopropenylium cation and a silyl anion rather than a bicyclic structure with a localized highly strained double bond. The reaction of base-stabilized Si4BBE with triphenylborane affords the [2+2] cycloadduct of Si4BBE and the dimer of an isomer of Si4BBE,tetrasilabicyclo[1.1.0]butan-2-ylidene (Si4BBY). The facile isomerization between Si4BBE and Si4BBY is supported by theoretical calculations and trapping reactions. Structure and properties of a heavy analogue of the smallest bridgehead alkene are disclosed.