Development and Application of New Steric Protection Group for Stabilization of Highly Reactive Organic Species

近年来，利用大体积基团的动力学稳定作用分离高活性化学物质的新方法受到了广泛的关注。本文提出了一种新的空间位阻保护的大体积基团，即。例如，本文报道了邻位带有（Me_3Si）_3C、（Me_3Si）_2CH、（Me_3Si）_2CMe的苯衍生物，并合成了各种新的含此基团的化合物。其中，2，4，6-三[双（三甲基硅烷基）甲基]苯基（Tb基）是特别有用的，因为它可以容易地由均三甲苯通过氯化和随后的三甲基硅化来合成，并且发现它比常用的2，4，6-三叔丁基苯基更大。将TbH溴化后与t-BuLi锂化得到的TbLi转化为空间体积很大的化合物Tb（Mes）MX_2（Mes = mesityl ; M=Si，Ge，Sn ; X=CL，H）。以Tb（Mes）MX_2为原料，合成了新的多硫化物和多硒化物Tb（Mes）MS_4（Y=S或Se），并通过X射线结构分析确定了它们的结构。这些化合物被认为是具有M=Y键的化合物（M=Si，Ge，Sn：Y=S，Se）的优良前体，Tb（Mes）MS_4（M=Ge，Sn）很容易与六甲基亚磷酰三胺反应生成产物，这些产物被认为是通过锗硫酮（Ge=S）和锡硫酮（Sn=S）生成的。多硒化合物Tb（Mes）MSe_4也具有类似的性质。

In recent years much attention has been paid to a new methodology for isolation of highly reactive chemical species which takes advantage of kinetic stabilization by sterically bulky groups. In the present study new bulky groups for stecric protection , i. e., benzene derivatives bearing (Me_3Si)_3C, (Me_3Si)_2CH, (Me_3Si)_2CMe at their o-positions, have been developed and various new compounds having this group have been prepared. Among them, 2, 4, 6-tris[bis (trimethylsilyl) methyl] phenyl group (Tb group) is especially useful baeuse it can be easily synthesized from mesitylene by chlorination and subsequent trimethylsilation and found to be bulkier than often used 2, 4, 6-tri-t-butylphenyl group. TbLi, obtained through bromination of TbH followedd by lithiation with t-BuLi, were converted into very sterically bulky compounds Tb (Mes) MX_2 (Mes = mesityl ; M=Si, Ge, Sn ; X=CL, H). New polysulfides and polyselenides Tb (Mes) MS_4 (Y=S or Se) were obtained from Tb (Mes) MX_2 and their structures were establised by X-ray structural analysis. These compounds are considered to be excellent precursors of compounds having M=Y bonds (M=Si, Ge, Sn : Y=S, Se) and indeed Tb (Mes) MS_4 (M=Ge, Sn) readily reacted with hexamethyl phosphorous triamide to give products which were considered to be formed via germanethione (Ge=S) and stannanethione (Sn=S). The polyselenides Tb (Mes) MSe_4 behaved similarly.