Dialkyl Ditellurium Compounds

Hydrogen telluride, generated in situ from aluminum telluride in aqueous tetrahydrofuran containing sulfuric acid, reacted with aliphatic aldehydes to produce dialkyl ditellurium compounds in yields of aproximately 50%. Strong acids are required to obtain acceptable yields of ditellurium compounds. Weak acids (acetic acid, chloroacetic acid) reduce the yields to approximately 10%. In a basic medium (triethylamine), no ditellurium derivative was formed the major product was the alcohol. 

Aliphatic halides react easily with disodium ditelluride to yield dialkyl ditellurium compounds. Although a systematic investigation of this reaction has not yet been carried out, primary alkyl chlorides, bromides and iodides, and secondary alkyl bromides produce the corresponding dialkyl ditellurium derivatives in good yields. 

This method was used to prepare the following dialkyl ditellurium compounds di(n-alkyl) ditelluriums2... 

Alkanetellurolates, that can be obtained from an organic lithium compound or a Grignard reagent and tellurium, are oxidized to dialkyl ditellurium compounds on contact with air. Di-t-butyl ditellurium, that is difficult to prepare by other routes, was obtained by this method in excellent yield1 2. The reaction of /-butyl magnesium chloride with tellurium proceeded in THF solution only in the presence of hexamethylphosphoric triamide2. 

From Other Dialkyl Ditellurium Compounds through Modification of the Organic Group... 

The saponification of bis[ditellurium compounds in refluxing 1 M aqueous/ethanolic sodium hydroxide are the only reported reactions modifying the organic group in dialkyl ditellurium compounds. 

Elemental chlorine, bromine, and iodine, sulfuryl chloride and thionyl chloride convert diorgano ditellurium compounds to organo tellurium trihalides (p. 314). The reactions are carried out in inert organic solvents with stoichiometrically required amounts of reagents. Dialkyl ditellurium compounds may lose alkyl halides if the halogenolysis is not performed under mild conditions at low temperatures. When equimolar amounts of halogens and diaryl ditellurium derivatives are combined in appropriate solvents, aryl tellurium halides are formed (p. 239). The formation of aryl tellurium halides is facilitated by stabilizing substituents in the orf/to-position to the tellurium atom or by the presence of thioureas or selenoureas in the reaction mixture. 

Diethyl ditellurium and bis[triethylgermyl] mercury yielded ethyl triethylgermyl tellurium3. Triorgano tin hydrides cleave the Te — Te bond in diaryl and dialkyl ditellurium compounds forming the organo triorganostannyl tellurium as one of the products (p. 191). 

The halogenolysis of dialkyl ditellurium compounds is a convenient method for the preparation of alkyl tellurium trihalides because dialkyl ditellurium compounds are easily accessible through alkylation of disodium ditelluride (p. 258). Diaryl ditellurium compounds generally obtained via reduction of organo tellurium trichlorides (p. 274), serve as starting materials for the syntheses of aryl tellurium tribromides and triiodides (Vol. IX, p. 1156) that are not obtainable from the hydrocarbons and tellurium telrabromide or tetraiodide. 

Alkyl tellurium halides, RTeX, in general, have no importance as starting materials for the preparation of alkyl tellurium trihalides. The alkyl tellurium halides are synthesized from dialkyl ditellurium compounds and elemental halogens. When alkyl tellurium trihalides are the desired products, there is no reason to prepare the monohalides first. However, when the tellurium monohalide is formed during the introduction of tellurium into an organic molecule, the reaction of this primary product with halogens is the method of choice for the preparation of the tellurium trihalides. This situation is realized for 3-oxo-l-propen-l-yl tellurium halides2,3. 

Diazonium chlorides also reacted with bis[2-chloro-2-phenylethenyl] ditellurium to produce aryl 2-chloro-2-phenylethenyl tellurium dichlorides1. Dialkyl ditellurium compounds have not yet been used in these reactions. 

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