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The first experimental evidence for the formation of an organic tellurium-centered radical (RTe•, R = Ph or nBu groups) during the hydrotelluration of alkenes and alkynes is provided. The radicals were detected by electronic paramagnetic ressonance (EPR), using DBNBS (3,5-dibromo-4-nitrosobenzenesulfonate) as the spin trap. The radical adducts (DBNBS/•TenBu and DBNBS/•TePh) presented an EPR spectrum characterized by a triplet of triplets due to one nitrogen and two equivalent hydrogen atoms (aN = 21.6 G and aH = 0.7 G) and a g value of 2.0060. The presence of tellurium radical adducts was confirmed by isotopic substitution (125Te) and by electrospray and chemical ionization mass spectrometry and MS/MS analysis. The products showed isotopic patterns expected for compounds containing Br and Te. These results provide evidence for organic tellurium-centered radical formation and suggest that the hydrotelluration reactions occur by a free radical mechanism.

Lithium diallylcyanocuprates generated by reaction of allyl halides with lithium n-butyltellurolate followed by transmetalation with lithium dibutylcyanocuprate react with vinyl triflates leading to highly unsaturated hydrocarbons.

The influence of the hydroxyl group in the regio- and stereochemistry of the reaction between p-methoxyphenyltellurium trichloride and 3-hydroxy alkynes is discussed. Mixtures of Z and E olefins, a...

Several chemical transformations on the side chain of functionalized vinylic tellurides were performed without affecting the tellurium−carbon bond. The stereochemistry of the double bond was maintained in some cases (protection and deprotection of alcohols); in other cases (acetal hydrolysis, oxidation, and reduction) some isomerization of the carbon−carbon double bond was observed.

Organotellurium trichlorides are efficiently reduced with sodium borohydride. The intermediate organo tellurolates are transformed into diaryl ditellurides, alkyl aryl tellurides, tellurides containing a cyclic ether, and vinylic tellurides.

Synthese par lithiation d'hydrocarbures halogenes de tellurure de phenylethynyl et d'alkyl. Ces composes conduisent a des ditellurures symetriques et des tellurures vinyliques non symetriques