Reaction of ketone hydrazones with TeCl: isolation and reactions of novel divinyl telluride.

The reaction of acetophenone hydrazones with TeCl4 in the presence of DBU gave a mixture of divinyl ditellurides and divinyl tellurides, which easily reacted with Cu powder in refluxing toluene to afford divinyl tellurides in good yields. The reaction of divinyl tellurides with bromine (1.2 eq.) gave the corresponding tellurium dibromide rather than the addition of the double bond whereas 3 molar amount of bromine gave excess brominated and oxidized products. The reaction of divinyl tellurides with 2-(trimethylsilyl)phenyl triflate in the presence of CsF gave (E)-2-alkenyldiaryl tellurides in good yields.