Arenetellurinic anhydrides

The readily accessible arenetellurinic anhydrides (see Section 3.6) exhibit oxidizing properties similar, in many aspects, to those of the diaryl telluroxides.  

Pyrrohdine, indoline, phthaloylhydrazide and 4-phenylurazole are unaffected by tellurinic anhydrides. 

Like p-methoxyphenyl teUuroxide, tellurinic anhydrides do not affect phenols but oxidize hydroquinones to the corresponding quinones, and oxidize thiols, thioesters, thioamides and phosphines to disulphides, esters, nitriles and phosphine oxides. 

In contrast to the teUnroxide, which oxidizes A, A/ -diphenylthiourea to M,A -dipheny-Inrea, tellnrinic anhydrides give M -diphenylcarbodiimide. 

Like teUnrones, and in contrast to teUnroxides, tellnrinic anhydrides oxidize benzylic alcohol to carbonyl componnds. 

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Arenetellurinic anhydrides are formed from the mixed anhydrides by hydrolysis, but a more convenient one-pot procedure for their preparation involves the reaction of phenyliodine(III) dicarboxylate with diaryl ditellurides in the two-phase system CH2CI2/H2O 10%. ... 

Oxytellurinylation.1 Arenetellurinic anhydrides oxidize 1-alkenes to Wc-di-.icetates in refluxing acetic acid. The actual reagent is assumed to be ArTe(0)0Ac. 

Arenetellurinic anhydrides are reduced to diaryl ditellurium compounds by sodium sulfide nonahydrate2 or dipotassium disulfite3. 

Carboxylic acids or carboxylic acid anhydrides react with arenetellurinic anhydrides in refluxing chloroform, in 1,2-dichloroethane, or in acetonitrile to give arenetellurinyl carboxylates. 

Arenetellurinic mixed anhydrides (general procedure) A solution of diaryl diteUuride (0.5 mmol) in methylene chloride (5 mL) was added to a stirred solution of phenyho-dine(III) dicarboxylate (1.5 mmol) in the same solvent (15 mL) at room temperature. The colour of diaryl diteUuride faded quickly. After stirring about 15 min the solvent was removed in vacuo and petroleum ether (15 mL) was added to the residue. The sohd was collected and recystallized from methylene chloride-petroleum ether or benzene-petroleum ether to give pure anenetellurinic mixed anhydride. 

Disulfides, diselenides, and ditellurides can be oxidized by hypervalent iodine compounds quite easily. Depending on the reaction conditions disulfides can be oxidized to sulfinic esters [59] or thiosulfonic S-esters [60,61]. Diselenides can be transformed into selenosulfonates [62]. Arenetellurinic mixed anhydrides are mild oxidants and can be obtained by oxidation of the corresponding ditellurides as shown in Scheme 9 [63]. Recently it was shown that a thioacetal based linker for solid-phase synthesis can be cleaved oxidatively using [bis(trifluoro-acetoxy)iodo]benzene 4 [64]. 

In this section, the reactions of electrophilic tellurium species will be considered. Among these species are tellurium tetrachloride 16, organotellurium halides 7, organotellurium trihalides 5, and also diorganoditellurides 4, since these species can be attacked by carbanions. Diorganotellurium oxides 8, arenetellurinic acid anhydrides 9, and other oxidizing agents will also be discussed in Section 9.13.6.3, since in these species the tellurium atom is electron deficient. 

Arenetellurinic acid anhydrides 137 present similar reactivity to the diaryltellurium oxides shown in Scheme 71. However, oxidation of the iV)./V-diphenylthiourea 138 with 137 gives the unexpected A,iV-diphenylcarbodimide 139 (Scheme 74).201... 

Diaryl ditellurium compounds are claimed to be oxidized by air5,6 and by selenous acid7 to arenetellurinic acid anhydrides. 

Arenetellurinic chlorides and carboxylic acid chlorides in refluxing carbon tetrachloride produced aryl tellurium trichlorides and carboxylic acid anhydrides. ... 

Only a few examples of arenetellurinyl carboxylates, the mixed anhydrides of tellurinic acids and carboxylic acids, are known. These eompounds were prepared by refluxing mixtures of arenetellurinic acid anhydrides with acetic or trifluoroacetic acid or their anhydrides in chloroform . Acetonitrile and 1,2-dichloroethane were also used as solvents. Benzenetellurinyl trifluoroacetate is described as a very hygroscopic, intractable oil. The arenetellurinyl acetates are solids with melting points of approximately 150°. 

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