Generation of an Organotellurium(II) Cation

Abstract

We expected that the chemical trapping products of low‐coordinated tellurenyl cation species can also be kinetically stabilized by the Tbt or Bbt group. Recently, we have reported the halogenation reactions of Bbt‐substituted ditelluride, BbtTeTeBbt, leading to the formation of the Te^II–Te^IV mixed‐valent tellurenyl fluoride, BbtTeTe(F)₂Bbt, and tellurenyl halides, BbtTeX (X = Cl, Br, I). During the dehalogenation reactions of these tellurium halides, it is rational to postulate the formation of a tellurenyl cation species as an intermediate. In this paper, we report the successful trapping of tellurenyl cation species with butadienes or triphenylphosphane, and the regeneration of the tellurenyl cation species by thermal retro [1+4] cycloaddition of the diene adducts.

Abstract

Organotellurium(II) cation species bearing a bulky aryl group were generated by dehalogenation from the correspondingtellurium(II) halides with silver salts or trimethylsilyl cations. In the presence of a diene or a phosphane as a trapping reagent, the tellurium(II) cations readily undergo [1+4] addition or phosphane coordination to form the diene and phosphane adducts, respectively.