Development of Synthetic Reactions Based on Radical Substitution Reactions at Tellurium Atoms

该项目旨在开发基于碲原子上的自由基取代反应的新型高效合成反应。所得结果总结如下。1.在自由基引发剂的存在下，烷基取代碲化物能有效地加成到乙炔上。利用该反应，建立了一种高效、立体选择性地由二烷基碲化物和乙炔合成二乙烯基碲化物的方法。2.碲化物与乙炔的加成反应具有区域选择性。高的区域选择性来自于加成反应过渡态取代基之间的空间排斥。3.碲化物中Te-C键的键裂以形成更稳定的自由基的方式选择性地发生。4.发现带有吸电子基团的碲化物与烯烃加成生成相应的碲化物。5.乙烯基碲化物通过与有机锂、-铝、-锌和-锆试剂反应进行金属转移反应，得到相应的有机金属化合物，其通过在过渡金属催化剂的帮助下与有机卤化物反应得到偶联产物。6.将碲化物与醛或环氧化物反应，再与乙炔加成，发展了一种合成烯丙醇和高烯丙醇的新方法。

This project was performed aiming at the development of new and efficient synthetic reactions based on radical substitution reactions on tellurium atoms. The obtained results were summarized below. 1.Alkyl substituted tellurides were found to add to acetylenes efficiently in the presence of a radical initiator. By use of this reaction, an efficient and stereoselective synthetic method of divinyltellurides from dialkyltellurides and acctylenes were established. 2.Addition of tellurides to acetylenes proceeded regioselectively. The high regioselectivity arises from steric repulsion between substituents at the transition state of the addition reactions. 3.Bond fission of Te-C bonds in tellurides occurred selectively in a fashion that the more stable radical is formed. 4.It was found that tellurides having an electron withdrawing group (s) add to olefins to give corresponding tellurides. 5.Vinyltellurides undergo transmetallation by the reaction with organolithium, -aluminum, -zinc, and -zirconium reagents to give corresponding organometallic compounds, which afforded coupling products by the reaction with organic halides by the aid of transition metal catalysts. 6.A new synthetic method of allylic and homoallylic alcohols was developed by the combination of the reaction of tellurides with aldehydes or epoxides and subsequent addition of the products to acctylenes.