Tellurenyl iodide

The treatment of LiN(SiMc3)2 with aryl tellurenyl iodides gives stable Ai,iV -bis(trimethylsilyl)tellurenamides that react with acetylenes to give acetylenyl tellurides (Eq. 2.4). 

These compounds are in principle easily accessible by the controlled halogenolysis of the parent ditellurides. However, the first compound obtained in 1959, 2-naphthyl-tellurenyl iodide, remained for a long time the only stable representative of this class until the preparation of other members of this class by a successful use of the same method." ... 

A one-pot reaction of phenylacetylene with a dialkyl ditelluride and an alkyl iodide under phase transfer catalysis (method a). The same product can be obtained by using the tellurenyl iodide prepared in situ (method b). ... 

This conversion involves the intermediacy of an iodonium ion which suffers the attack of the iodide anion, promoting cycUzation through the tellurenyl iodide (pathway a) or by the direct pathway b. 

At the same time, oxidation of tellurenyl iodide 19 with bromine occurs with fission of the Te-I bond, probably, through formation of the mixed tellurium trihalide 20 (86JOC1692) (Scheme 10). 

When such groups are not present, the organotellurium halide cannot be isolated. In these cases, aryl, alkenyl, and alkyl tellurenyl halides, usually bromides and iodides, are prepared and used in situ. ... 

Organo tellurium halides, also named organo tellurenyl halides, are in principle easily accessible through controlled halogenolysis of diorgano ditellurium compounds. However, 2-naphthyl tellurium iodide, prepared in 19592 from bis[2-naphthyl] ditellurium and iodine, remained the only compound of this type until 1971/72, when a series of ortho-carbonyl substituted phenyl tellurium halides were synthesized3-4. Aryl tellurium halides without substituents in the ortho-position to tellurium were isolated and characterized in 1975s. 

If the diaryl ditelluride is previously converted in situ into the corresponding tellurenyl halide, both the electrophilic tellurium moieties are used. (The stable crystaUine 2-naph-thylteUurenyl iodide (see Section 3.7) reacts similarly.) The reaction is of general application, giving high yields of the expected tellurides with aromatic, aliphatic, cycloaliphatic, vinylid and acetylenic Grignard reagents, under mild conditions. 

The reaction of organic ditellurides with halogen leads to the formation of tellurenyl hahdes [65]. 2-Naphthyltellurenyl iodide is isolated by using this method, as exemplified by Scheme 15.22. 

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