From Lithium or Sodium Tellurides

6-Diorgano-4-oxo-4H-tellurins were formed in 37 67% yield from dilithium or disodium telluride and bis[organoethynyl] ketones .  

A similar reaction with bis[tcrr-butyldimethylsilyl] tellurium as the source of tellurium gave a yield of only 19%.  

6-Diphenyl-4-oxo-4//-tellurin 120 ml (0.12 mol) of a 1.0 molar solution of lithium triethylborohydride in tetrahydrofuran are added to 7.65 g (60 mmol) of powdered tellurium under nitrogen and the mixture is stirred at 20 for 4 h. A solution of sodium cthoxide [prepared from 5.52 g (0.24 mol) of sodium and 240 m/ of absolute alcohol] is added to the dilithium telluride. 13.8 g (60 mmol) of bis[phenylethynyl] ketone are dissolved in a mixture of 150 ml of tetrahydrofuran and 150 ml of 1 molar sodium ethoxide in ethanol and this solution is poured as quickly as possible into the deep purple colored dilithium telluride solution. The flask containing the reaction mixture is immediately placed in a water bath at 50° and the temperature of the water bath is slowly increased over 30 min until ethanol begins to condense on the side of the flask. The water bath is removed and the mixture is stirred overnight at 20°. 400 ml of dichloromethane are then added, the resultant mixture is washed with 800 ml of dichloromethane, and the organic phase is separated and concentrated to an oil. The oil is dissolved in 600 ml of dichloromethane, and the solution is filtered through a pad of sand. The filtrate is washed with 200 ml of 2% aqueous sodium chloride solution, dried with anhydrous sodium sulfate, filtered, and evaporated. The brownish solid residue is triturated with 20 ml of butanenitrile and the fine yellow solid is collected by filtration yield 10.9 g (51%) m.p. 126-129° (from acetonitrile). 

When l-phenyl-5R-3-oxo-l,4-pentadiynes were used as starting materials, A-oxo-AH-tellurins with different substituents in the 2- or 6-positions were obtained  

Chlorine, bromine, or iodine react with 2,6-disubstituted 4-oxo-4/f-tellurins to produce the 7e,7e-dihalides.  

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