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

1.合成了一个带有Martin配体的五配位的3-甲氧羰基-1，2-氧杂磷杂环丁烷，这是首次在1，2-氧杂磷杂环丁烷的3-位上引入吸电子基团如羰基。还成功地合成了一种新型的含两个1，2-氧杂磷杂环的螺正膦。2.五配位的1，2-oxasiletanides，彼得森反应的中间体，已获得相应的β-羟基硅烷，这是通过依次处理的乙烯基硅烷带有马丁配体与t-BuLi，然后与羰基化合物，与KH在18-冠-6的存在下制备的。类似地，已经合成了五配位的1，2-oxastannetanide和1，2-oxagermetanide，尽管在前一种情况下不需要Martin配体的稳定化。这些化合物的X射线晶体学分析表明，这些化合物具有畸变的三角双锥结构，在顶点位置具有两个或一个（在oxastannetanide的情况下）氧原子。3.在Et_3N存在下，用溴氧化环化相应的双羟基硫族化合物，合成了四配位的1，2-氧硫杂环丁烷和1，2-氧硒杂环丁烷，X射线衍射分析表明它们具有准三角双锥结构。4.第14族和第15族元素化合物的热分解通过弱极性过渡态定量地给出了相应的烯烃。而第16族元素化合物的热分解没有生成Wittig反应产物，而是生成了由硫族元素-氧键的异裂引起的迁移产物。非常有趣的是指出，在1，2-氧硫杂环丁烷的热分解的情况下，得到痕量的Corey-Chaykovski反应产物环氧乙烷。这些结果已作为简短的通讯发表。

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.