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

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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.