From tellurium tetrachloride and alkynyllithium compounds

In a related procedure, tellurium tetrachloride is treated with lithium amides giving tellurium(II) amides via the successive reduction and amination of TeCl4. 

These species, which provide Te + electrophiles, react with alkynyllithium reagents, giving dialkynyl teUurides in moderate yields.  

The diynes (R — = — = -R ) are formed as by-products, therefore suggesting that the previously described reaction of TeCl4 with 4 mol equiv of the lithium alkynyls is partially operative. 

3 Synthesis of internal acetylenes from vinylic tellurides 

Treatment of vinylic tellurides prepared by photopromoted carbotelluration of terminal acetylenes (see Section 3.16.3) with aqueous NaOCl, followed by pyrolysis, affords internal acetylenes in good yields.  

---