Tellurides, aryl phenyl

ArsBi bearing ortho methoxy groups mediates dehydrative condensation of a-monosubstituted carboxylic acids with alcohols and amines (Scheme 14.139) [288]. Macrocyclic esters can be synthesized by the ArsBi-templated reaction of diols with dicarboxylic acid derivatives [289]. The Bi-C bonds of Ar Bi are cleaved by diphenyl diselenide and ditelluride to give aryl phenyl selenides and tellurides, respectively (Scheme 14.140) [290]. The reaction of ArsBi with elemental chalcogen (E Se, Te) affords a mixture of the respective dichalcogenides (ArEEAr) and monochalcogenides (ArEAr). 

In a range of anions PhZ (Z = O, S, Se, Te), for example, the thiophenolate ion (PhS ) effectively traps aryl radicals (Ar ), whereas the anion of phenyl selenide (PhSe ) is 20 times less active, and the phenolate anion (PhO ) is absolutely inactive. The reaction of aryl radicals with phenyl-telluride ions (PhTe ) proceeds in an abnormal fashion—both asymmetrical and symmetrical tellurides are produced (Rossi and Pierini 1980). 

The reaction of tellurium with acetylene and iodobenzene in the presence of potassium hydroxide, hexamethylphosphoric triamide, tin(II) chloride, and water under 12 atm acetylene in an autoclave at 100-120° produced diphenyl tellurium, phenyl vinyl tellurium, and divinyl tellurium4. Diphenyl tellurium could be the product of the arylation of the telluride dianion by phenyl iodide. 

Acetylenes react with arenetellurolates to form aryl vinyl tellurides. The vinyl groups in vinyl aryl telluriums are converted to vinyl carboxylic acids by carbon monoxide in the presence of stoichiometric amounts of palladium dichloride1 or diacetate2 4. The yield and the product distribution is influenced by the reaction time, the CO pressure, the presence or absence of lithium chloride or triethyl amine, and the concentration of palladium salt. Diphenyl tellurium was converted to benzoic acid1,3. Hexyl phenyl tellurium formed only benzoic acid and no heptanoic acid1. 

Treatment of alkali metal alkyl or aryltellurolates (Sections) with alkyl halides, aryl halides, alkenes, or alkynes have been nsed to prepare unsymmetrical tellurides, as exemplified by the reaction of sodium phenyl teUurolate or paramethylphenyl tellnrolate with PhC CHCOPh. ... 

Treatment of oestrone with tetraphenylbismuth monotrifluoroacetate gave oestrone phenyl ether and exemplified, in part, a new procedure for aryl ether formation.31 A detailed study was reported of the formation of benzyl ethers by sequential reaction of alcohols with chloro(phenylmethylene)dimethylammonium chloride and sodium hydrogen telluride.32 Steroidal alcohols, inter alia, were converted into hydrolytically stable silyl ethers by reaction with B N Sil or BulPh2I which were generated in situ from the selenosilane and iodine.33 The 5a-hydroxycholestane (21) was protected in this way. 

Alkynil zinc reagents have also been employed to afford coupling reactions with phenyl-butyl telluride and aryl iodides. ... 

Conditions have been worked out for the synthesis of methyl polyfluoroalkyl sulphides and 2-bromo-l,l-difluoroethyI phenyl sulphide by halogen-substitution reactions involving sodium thiolates. / -Nitrothiophenol reacts with 1,2-dichlorohexafluorocyclopentene to give the l,2-bis(p-nitrophenylthio)-analogue. Aryl alkyl tellurides PhTeR and bis(phenyltelluro)methane PhTeCHgTePh can be obtained from PhTeLi and an alkyl halide, or di-iodomethane, respectively. 

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