Aryl alkyl tellurides

The tellurolate anion formed can be alkylated in situ, giving alkyl aryl tellurides, if the above reaction is effected in the presence of a phase transfer catalyst. Otherwise, performing the reaction in the presence of the reducing agent TUDO a telluride yield near to quantitative is generated, owing to the reduction of the aryl tellurinate anion to aryl tellurolate. ... 

Diorganyl mono- and ditellurides are the best-known classes of organic tellurium compounds comprising symmetric and unsymmetric alkyl, aryl, and alkyl-aryl tellurides. In addition to acyclic tellurides, heterocychc aliphatic telluroethers as well as aromatic tellurophene-derivatives are known (for a review, see Ref 36). 

The diaryl telluride, alkyl aryl telluride, and dialkyl telluride carrying sulfopropyl groups were prepared and were found to be the most efficient tellurium based inhibitors of thioredoxin reductase ever tested. The results clearly showed that of the four cyclic aryl alkyl chalcogenides 162-165, all primitive analogues of vitamin E, only the tellurium compound, 165, showed interesting inhibition characteristics. 

A series of primary and secondary alkyl aryl tellurides has been found to undergo rapid (3-10 min) group-transfer cyclization to afford tetrahydrofuran derivatives in good yields (60-74%) under micro vave heating conditions at 250 °C in ethylene glycol or at 180 °C in vater, the only dra vback of the process being the loss in dia-steroselectivity as a consequence of the higher reaction temperature [22]. Li and coworkers have developed a successful method for synthesis of vinyl cycloethers by direct addition of THF and 1,4-dioxane to alkynes reaction occurs at 200 °C in 40-180 min under the action of microwave irradiation (300 W) [23]. 

The arylmethylselenides ArSeMe and tellurides ArTeMe pose somewhat of a special case in the alkyl aryl compounds, due to the comparatively low reactivity of their radical cations, which do not easily undergo cleavage of the chalcogen-methyl bond, due to the low stability of the resulting methyl radical or cation. 

Alkyl, aryl, allyl, benzyl, vinyl, ethynyl tellurides, tellurobutadienes, divinyltellurides, tellurobutenines, telluro(thio)- and telluro(seleno)ketene acetals and j3-(phosphorovinyl) tellurides are susceptible to such exchange, giving the corresponding lithium compounds trapped in sequence with selected electrophiles. ... 

Radical accumulators whose presence might facilitate addition to / -mono and / ,/ -disubstituted olefins were conceived. It seemed to us that alkylaryl or dialkyl tellurides should react with alkyl radicals and give an intermediate radical of type R1R2R8Te (an expanded valence shell) which might have a relatively longer life on the radical time scale. A secondary objective would be the exchange of one radical against another. In this way, the special nucleophilic properties of the aryl telluride anion for example, could be exploited to make complex natural product derived radicals. 

Aryl tellurides can be prepared by utilization of Grignard or alkyl lithium reagents, since elemental tellurium can conveniently be inserted into Mg-C or Li-C bonds. The one-pot synthesis of tetratellurafulvalene illustrates the use of... 

LTA oxidizes diaryl tellurides to diaryltelluiium diacetates, while the treatment of diaryl, divinyl, alkyl aryl and dialkyl tellurides with PdfOAch or LijPdCU results in a new carbon-carlxm bond being formed (equations 48 and 49). 

Tellurides 135 were treated with a phenacyl halide, diethyl bromomalonate, or diethyl dibromomalonate to afford a selection of 2-alkyl/aryl-2-halo-l,2-oxatellurolanes 136 (Equation 28) <1997H(45)575, 2000SC979>. 

It has been reported that sodium-, potassium- calcium- and magnesium-tellurium exchanges are achieved by similar procedures with alkyl, aryl, ethynyl, vinyl, allyl and benzyl tellurides. ... 

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