Synthesis and Thermolysis Mechanism of Oxetanes Containing a Highly Coordinate Main Group Element

1. 本文首次合成了含马丁配体的五配位3-甲氧羰基-1,2-氧磷烷，并在3位上有羰基等吸电子基团。还成功地合成了一种含有两个1,2-氧膦烷环的新型螺旋磷烷。2. 以含马丁配体的乙烯基硅烷依次用t-BuLi和羰基化合物，在18-冠-6的存在下用KH进行处理，得到相应的β -羟基硅烷去质子化反应，得到彼得森反应的中间体-五配位1,2-氧基硅烷。类似地，已经合成了一种五坐标1,2-奥沙坦尼酯和1,2-奥沙格美坦尼酯，尽管在前一种情况下不需要马丁配体的稳定。这些化合物的x射线晶体学分析表明，这些化合物具有扭曲的三角双锥体结构，在顶端位置有两个或一个氧原子（在奥伐他坦胺的情况下）。3. 在Et_3N的存在下，将相应的二羟基硫族化合物与溴氧化环化，合成了四配位的1,2-草酸乙烷和1,2-草酸乙烷。x射线晶体学也表明它们具有伪三角双锥体结构。4.14族和15族元素化合物的热裂解通过微极性过渡态定量地得到相应的烯烃。然而，16族元素化合物的热裂解没有产生Wittig反应产物，而是由硫氧键异解引起的迁移产物。有趣的是，在1,2-草硫烷热裂解的情况下，得到了微量的Corey-Chaykovski反应产物氧环烷。这些结果以简短的通讯形式发表。

1. A pentacoordinate 3-methoxycarbony1-1,2-oxaphosphetane bearing the Martin ligand has been synthesized as the first example for 1,2-oxaphosphetane with an electron-withdrawing group such as carbonyl group at the 3-position. A novel type of spirophosphorane containing two 1,2-oxaphosphetane rings has also been synthesized successfully. 2. Pentacoordinate 1,2-oxasiletanides, intermediates of the Peterson reaction, have been obtained by deprotonation of the corresponding beta-hydroxy silanes, which were prepared by sequential treatment of the vinylsilane bearing the Martin ligand with t-BuLi and then with carbonyl compounds, with KH in the presence of 18-crown-6. Similarly, a pentacoordinate 1,2-oxastannetanide and 1,2-oxagermetanide have been synthesized, although stabilzation by the Martin ligand is not necessary in the former case.X-ray crystallographic analyzes of these compounds indicate that these compounds have a distorted trigonal bipyramidal structures with two or one (in the case of the oxastannetanide) oxygen atom (s) at the apical position (s) . 3. Tetracoordinate 1,2-oxatthietane and 1,2-oxaselenetane were synthesized by oxidative cyclization of the corresponding bis (hydroxy) chalcogenides with bromine in the presence of Et_3N.It was also indicated by X-ray crystallography that they have pseudo-trigonal bipyramidal structures. 4.Thermolyses of the group 14 and 15 element compounds gave quantitatively the corresponding olefins via a slightly polar transition state. However, themolyses of group 16 element compounds afforded no Wittig reaction products, but migration products induced by the heterolysis of the chalcogen-oxygen bond. It is very interesting to point out that a trace of Corey-Chaykovski reaction product, oxirane, was obtained in the case of thermolysis of 1,2-oxathietane. These results have been published as short communications.