Diethyl ditelluride

Diethyl ditelluride and dibenzyl ditelluride are prepared similarly in yields of 71% and 82%, respectively. 

Diphenyltellurophene is obtained by treatment of diethyl ditelluride with diphenyldiacetylene in N2H4-KOH-DMSO-H2O at 55 °C (DMSO = dimethyl sulfoxide Scheme 17) <2002KGS280>. 

Method C2 (typical procedurep A 5% solution of NaBH in 5% NaOH is added dropwise to a stirred suspension of bis(2-thienyl) ditelluride (0.75 g, 1.78 mmol) in EtOH under N2, until disappearance of the red colour of the solution. 2-Bromocholestan-3-one (0.80 g, 1.72 mmol) in EtOH (5 mL) is then added dropwise over 10 min, causing an immediate red colouration. After 30 min the mixture is poured into HjO/diethyl ether, and the organic phase is washed several times with HjO and dried (CaClj). Evaporation of the solvent and chromatography (Si02/CH2Cl2) gives cholestan-3-one (0.62 g (93%) m.p. 127-128°C). 

Lithium tris(trimethylsilyl)silyltellurolate bis(tetrahydrofuran) is a pale yellow, air-sensitive solid that is soluble in hydrocarbons, diethyl ether, and THF. The finely powdered solid oxidizes (sometimes pyrophorically) in air to give the dark green ditelluride (SiMe3)3SiTeTeSi(SiMe3)3.8 The lithium tellu-rolate is dimeric in the solid state as shown by X-ray crystallography10... 

Organo Vinyl Tellurium (from Vinyl Tellurium Iodides) A solution of the vinyl tellurium iodide, prepared by addition of 0.25 g (1.0 mmol) iodine in benzene to the divinyl ditelluride (1.0 mmol) in 5 ml tetrahydrofuran at 0° under nitrogen, is added dropwise to a solution of the organo magnesium bromide in 10 m/ tetrahydrofuran at 0°. The mixture is stirred at 20° for 1 h, hydrolyzed with a saturated aqueous solution of ammonium chloride, extracted with diethyl ether, the extract dried with magnesium sulfate and evaporated. The product is chromatographed on silica gel with petroleum ether (30-60°)/ethyl acetate (9 1) as eluent. The following compounds were prepared in this manner (yields in parentheses are for the reactions with vinyl tellurium iodides) ... 

Sodium dithionite in water or aqueous dimethylformamide is an economic, efficient system for the dehalogenation of a-halo-ketones. Other reagents that have been described recently for dehalogenation include iron-graphite (prepared by reduction of ferric chloride with potassium-graphite), sodium 0,0-diethyl phosphorotelluroate, and sodium borohydride in the presence of a catalytic amount of bis(2-thienyl) ditelluride. ... 

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