Stereochemistry and Mechanism of Chlorotelluration of Olefins

Article abstract of DOI:10.1021/jo00170a009

The stereochemistry of the addition of TeCl4 and 2-naphthyltellurium trichloride, respectively, to (E)-2-butene, (Z)-2-butene, 1-(E)-deuterio-1-decene, cyclopentene, cyclohexene, and cyclooctene was studied by means of 1H nuclear magnetic resonance spectroscopy.The addition of 2-naphthyltellurium trichloride was completely anti stereospecific, whereas TeCl4 usually gave mixtures arising from syn and anti addition. p-Benzoquinone was highly effective in promoting syn addition to all olefins investigated when present in a catalytic amount (15-20percent).An ionic mechanism involving a telluronium ion intermediate is suggested for the addition of 2-naphthyltellurium trichloride.A more or less concerted, stereospecific syn addition and a competing radical chain reaction are proposed as the major pathways for the addition of TeCl4 to olefins.