Diorgano ditellurides

Diorgano diselenides have been used extensively as precursors to seleninic acids in the presence of hydrogen peroxide.The catalytic activity of preformed seleninic acids and seleninic acids generated in situ are identical. Diorgano ditellurides have also been used as catalysts in thiolperoxidase-like reactions for the oxidation of thiols with various peroxides. However, tellurinic acids are not thought to be involved even though RTe(=0)SPh types of structures are proposed as intermediates. 

Dihydrofolate reductases (DHFR), 48, 54, 56 Dimethyl chalcogenides, 131-133 Dimethylselenide, 131-133 Dimethyltellurides, 131-133 Diorgano diselenides, 113 Diorgano ditellurides, 113 Diorganochalcogen(IV) dihalides crystallographic structure, 80f redox reactions, 90 Diorganoselenides... 

Anti-tellurosulphonation of 1-alkynes.A solution of alkyne (1.1 mmol), sodium arylsul-phinate (5 mmol) and diorgano ditelluride (0.5 mmol) in 5 mL of 80% aqueous acetic acid was heated at 80°C for 24 h (R=Ph, 5.2 h). The reaction mixture was diluted with 20 mL of AcOEt, washed with saturated aqueous sodium bicarbonate, dried over Na2S04 and concentrated in vacuum. Crude products, were concentrated under vacuum, and the residues were purified by preparative TLC on silica gel (AcOEt/hexanes, 1 10), treated with 1 equiv of Br2 in AcOEt and concentrated under vacuum. The residues were purified by recrystallization with CH3OH/HCCI3. 

Trialkylboranes were converted into alkyl phenyl selenides and alkyl phenyl tellurides by reactions with PhSeSePh and PhTeTePh in the presence of stoichiometric amounts of air.550 Vinyl selenides and tellurides were synthesized by treating vinylboronic acids or esters with phenylselenyl chloride in ionic liquids (Equation (114))551 or by palladium-catalyzed coupling reaction of diorgano ditellurides (Equation (115)).552... 

Vinylic tellurides from vinylboranesfr To a solution of cyclohexene (10 mmol) in THF (10 mL) was added a solution of diborane (5 mmol) in THF at 0°C with stirring the precipitate thns formed [(c-Hex)2BH] was stirred at 0°C for 1 h. The reaction mixtnre was dilnted with a solution of a terminal acetylene (5 mmol) added at - 10°C, and the mixture was kept at 0°C for 2 h. After the precipitate had dissolved, the resulting solution was treated with 3 M NaOH (2ml.), diorgano ditelluride (4 mmol) and 3% Pd(PPh3)4, then was reflnxed for 3 h under N2. After the reaction was complete normal work-up was performed. Ymyltellurides were isolated and pnrilied by TLC with petrolenm ether (30-60°C) as developer. 

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