Elemental tellurium in organoelement synthesis of tellurium-containing organometallics and telluracycles

An overview presents the known methods of using elemental tellurium in the synthesis of various acyclic and cyclic, saturated and unsaturated compounds containing Te–E bonds (E = main group atom or transition metal atom). These methods include the insertion of tellurium into the C–E (E = halogen, Al, Ga, Sn, Zr) and P–E (E = Li, P, Si, Ge and Sn) and Sn–Sn single bonds and the addition to the E = E (E = Si, Ge and Sn) double bond, and PC triple bond, as well as the breakdown of the CC double bond and the exchange of metal (Hg, Ag) and non-metal (B, I) for Te. Reactions with carbenes, their heavier (Si, Ge, Sn) analogs and free radicals are also discussed, as are the oxidation of organophosphorous (III) compounds, silanes and germanes with Te and the direct cyclisation of alkanes, arenes and heteroarenes containing two halogenomethyl fragments with elemental Te. Three-component heterocyclizations involving elemental tellurium and leading to telluracycles are also discussed. The reactions mentioned above are compared to those involving lighter chalcogens.