From Diorgano Tellurium Dihalides

Aryl alkyl tellurium dihalides will lose alkyl halides on heating. The aryl tellurium halide products will disproportionate to the corresponding diaryl ditellurium in a basic environment (p. 154, 387). 

Bis[3-thienyl] Ditellurium [Pyridine Method] In 50 ml of dichloromethane are dissolved 26.8 g (0.1 mol) of butyl 3-thienyl tellurium and 13.5 g (0.1 mol) of sulfuryl chloride are added to the stirred solution. The dichloromethane is evaporated, 100 ml of pyridine is added to the residue, the mixture is heated under reflux for 0.5 h, and then hydrolyzed with dilute hydrochloric acid. Water is decanted, the residue is extracted with boiling chloroform, and the chloroform extract is dried, filtered, and evaporated yield 12 g (57%) m.p. 99°. Similarly prepared were  

4-bromophenyl butyl tellurium dibromide bis[2-bromo-6-methoxyphenyl] ditellurium from 2-bromo-6-methoxyphenyl butyl tellurium dichloride 

These reactions are of synthetic importance only when the aryl alkyl tellurium compounds are easily accessible. Such aryl alkyl tellurium compounds are obtained when an aryl lithium compound generated from an aryl halide and alkyl lithium is treated with tellurium (p. 154, 387). 

The reduction of aryl alkyl tellurium dihalides in which the alkyl group bears an electronegative substituent (chlorine, oxygen) on the )S-carbon, cleaves the alkyl group and forms diaryl ditellurium compounds. Sodium sulfide , sodium hydrogen sulfite, hydrazine sulfate, and zinc effect this conversion. 

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From Diorgano Tellurium Dihalides and Water or Aqueous Base... 

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