Experimental and theoretical studies on formal σ-bond metathesis of silyl tellurides with alkyl halides

Silyl tellurides reacted with alkyl halides under mild thermal conditions to give the corresponding alkyl tellurides and silylhalides in good to excellent yields. Substitution took place much faster in polar solvents, such as acetonitrile, than that in non-polar solvents. After removal of the volatile silyl halides and solvent under vacuum, the essentially pure divalent organotellurium compounds were obtained. Theoretical calculations were performed to understand the reaction mechanism, and a stepwise pathway involving tetravalent organotellurium intermediate was obtained. Since the intermediate as well as the rate-determining step leading to the intermediate from the reactants possess highly polar character, they would be stabilized in polar solvents.