Benzenetellurinic Anhydride1

[94971-86-5]  · C12H10O3Te2  · Benzenetellurinic Anhydride  · (MW 457.41)

(mild and selective oxidizing agent by itself and as mixed anhydrides;1-3 catalyst for hydration of ethynyl group;3 vicinal syn diacetoxylating agent of alkenes;4 electrophiles, as mixed anhydrides, for acetoxytellurinylation of alkenes, cyclofunctionalization of hydroxyalkenes,5 aminotellurinylation of alkenes, cyclofunctionalization of alkenic carbamates,6 one-pot synthesis of 2-oxazolidinones from alkenes,7 amidotellurinylation of alkenes8 as well as alkynes,9 one-pot synthesis of 2-oxazolines from alkenes8 as well as oxazoles from alkynes,9 and one-pot conversion of allylsilanes to allylamines10)

Physical Data: mp 220-225 °C.

Solubility: almost insol in common organic solvents except acetic acid. In acetic acid it gradually changes to the mixed anhydride, benzenetellurinyl acetate.

Preparative Methods: benzenetellurinic anhydride is readily obtained as a white solid by alkaline hydrolysis of phenyltellurium trihalides and subsequent acidification with AcOH or by oxidation of Diphenyl Ditelluride with air or selenous acid.1 The following arenetellurinic anhydrides are prepared similarly: 4-ethoxybenzene-, mp 234-238 °C (dec); 4-hydroxybenzene-, mp 200 °C (dec); 4-methoxybenzene-, mp 200-205 °C; 4-methylbenzene-, mp 200 °C; 4-phenoxybenzene-, mp 276 °C; 2-naphthalene-, mp 230 °C.1

Purification: it was reported that the anhydride could be recrystallized from acetic acid.11

Handling, Storage, and Precautions: the anhydride is hygroscopic. It must be dried over P2O5 before use and stored as such. Toxicity of this compound is not well-defined. All manipulations are recommended to be done with gloves and in a fume hood.

Oxidation.

Benzenetellurinic anhydride and its congeners1 readily oxidize thiols to disulfides, phosphines to phosphine oxides, hydroquinones to quinones, thioamides to nitriles, thioesters to esters, xanthates to thioesters, thioureas to carbodiimides, benzyl alcohols to benzaldehydes, and benzoin to benzil, respectively.2,3 The mixed anhydrides (PhTe(O)OX; X = Ac, C(O)CF3, SO2CF3) exhibit similar reactivities as the parent anhydride but also show some different selectivities to thioamides and thioureas to afford thiadiazole and urea derivatives, respectively.3b

Catalysis for Ethynyl Hydration.

The p-ethoxy congener catalyzes hydration of terminal alkynes in refluxing acetic acid but is inert to internal alkynes (eq 1).3a

Vicinal syn Diacetoxylation.

Under the catalysis of sulfuric acid, the reagent oxidizes alkenes in AcOH to afford vicinal syn-diacetates (eq 2).4 The reaction was assumed to be initiated by benzenetellurenic acid derivatives generated reductively and to proceed via trans acetoxytellurenylation followed by SN2 displacement of the PhTe group by AcOH.

Electrophiles for Acetoxytellurinylation of Alkenes and Cyclofunctionalization of Hydroxyalkenes.

The reagent and its congeners react with alkenes in AcOH to give acetoxytellurinylation products, which are reduced to Markovnikov-type b-acetoxytellurides. They also induce cyclofunctionalization of hydroxyalkenes to 5-, 6-, and 7-membered cyclic ethers. Treatment of the reagents with AcOH or its anhydride readily afford their mixed anhydrides (eq 3; Ar = Ph, p-MeOC6H4-, 2-naphthyl; X = MeCO), which become soluble in common solvents such as CH2Cl2 and CHCl3 and perform the same transformation much more rapidly under the catalysis of Lewis acids such as Boron Trifluoride Etherate. These reactions are highly regio- and trans stereoselective (eq 4).5

Electrophiles for Aminotellurinylation, Cyclofunctionalization of Alkenic Carbamates, and One-Pot Synthesis of 2-Oxazolidinones from Alkenes.

The mixed anhydrides of this reagent (eq 3; Ar = Ph, X = MeCO, CF3CO) with carbamates effect regio- and stereoselective aminotellurinylation of alkenes in the presence of BF3.OEt2 in CHCl3 to give (2-phenyltellurinyl)alkyl carbamates. The triflate (eq 3; Ar = Ph, X = CF3SO2) does it under milder conditions without Lewis acid. This reaction can be extended to cyclofunctionalization of alkenic carbamates into nitrogen heterocycles (eq 5).6 When the aminotellurinylation is carried out at higher temperature, 2-oxazolidinones are obtained in high yields via a regio- and stereoselective path combined by trans addition and intramolecular SN2 substitution of the PhTe(O) group (eq 6).7

Electrophiles for Amidotellurinylation of Alkenes and Alkynes, and for One-Pot Synthesis of 2-Oxazolines and Oxazoles from Alkenes and Alkynes, respectively.

The mixed anhydride of the reagent (eq 3; Ar = Ph, X = CF3CO) in the presence of BF3.OEt2 effects amidotellurinylation of alkenes in MeCN at rt to give 2-acetamidoalkyl phenyl telluroxides, which suffer further intramolecular SN2 substitution at higher temperature to afford 2-oxazolines in high yields. These reactions are highly regio- and stereoselective (eq 7).8 The trifluoromethanesulfonic anhydride (eq 3; Ar = Ph, X = CF3SO2) combined with MeCN undergoes (E) stereoselective amidotellurinylation of alkynes in the presence of a protonic acid. The addition products from terminal alkynes isomerize thermally to (Z)-b-acetamidovinyl phenyl telluroxides, whereas those from internal alkynes are transformed into oxazoles via a spontaneous intramolecular cyclization (eq 8).9

Electrophile for One-Pot Conversion of Allylsilanes to Allylamines.

In the presence of BF3.OEt2 in ClCH2CH2Cl, the mixed anhydride of this reagent (eq 3; Ar = Ph, X = CF3CO) converts at rt allylsilanes to allyl phenyl telluroxides, which are treated in situ with primary or secondary amines at 65 °C to give the corresponding allylamines. The transformation is highly stereoselective. Thus g-substituted allylsilanes with arylamine give g-substituted allylamines but with alkylamine give a-substituted allylamines (eq 9).10


1. (a) Barton, D. H. R.; Finet, J.-P.; Thomas, M. T 1986, 42, 2319. (b) Hu, N. X.; Aso, Y.; Otsubo, T.; Ogura, F. PS 1988, 38, 177. (c) Ogura, F.; Otsubo, T.; Aso, Y. PS 1992, 67, 223. (d) Irgolic, K. J. MOC 1990, E12b, 349, 355. (e) Petragnani, N.; Comasseto, J. V. S 1991, 793, 897.
2. (a) Barton, D. H. R.; Ley, S. V.; Meerholz, C. A. CC 1979, 755. (b) Ley, S. V.; Meerholz, C. A.; Barton, D. H. R. TL 1980, 21, 1785. (c) Ley, S. V.; Meerholz, C. A.; Barton, D. H. R. T 1981, 37(Suppl. 9), 213.
3. (a) Hu, N. X.; Aso, Y.; Otsubo, T.; Ogura, F. TL 1986, 27, 6099. (b) Fukumoto, T.; Matsuki, T.; Hu, N. X.; Aso, Y.; Otsubo, T.; Ogura, F. CL 1990, 2269.
4. Kambe, N.; Tsukamoto, T.; Miyoshi, N.; Murai, S.; Sonoda, N. CL 1987, 269.
5. (a) Hu, N. X.; Aso, Y.; Otsubo, T.; Ogura, F. TL 1987, 28, 1281. (b) Hu, N. X.; Aso, Y.; Otsubo, T.; Ogura, F. JOC 1989, 54, 4391.
6. (a) Hu, N. X.; Aso, Y.; Otsubo, T.; Ogura, F. CL 1987, 1327. (b) Hu, N. X.; Aso, Y.; Otsubo, T.; Ogura, F. JOC 1989, 54, 4398.
7. (a) Hu, N. X.; Aso, Y.; Otsubo, T.; Ogura, F. CC 1987, 1447. (b) Hu, N. X.; Aso, Y.; Otsubo, T.; Ogura, F. JOC 1989, 54, 4398.
8. (a) Hu, N. X.; Aso, Y.; Otsubo, T.; Ogura, F. TL 1988, 29, 1049. (b) Hu, N. X.; Aso, Y.; Otsubo, T.; Ogura, F. JCS(P1) 1989, 1775.
9. (a) Fukumoto, T.; Aso, Y.; Otsubo, T.; Ogura, F. CC 1992, 1070. (b) Fukumoto, T.; Aso, Y.; Otsubo, T.; Ogura, F. HC 1993, 4, 511.
10. Hu, N. X.; Aso, Y.; Otsubo, T.; Ogura, F. TL 1988, 29, 4949.
11. Dereu, N. L. M.; Zingaro, R. A.; Meyers, E. A. OM 1982, 1, 111.

Fumio Ogura & Tetsuo Otsubo

Hiroshima University, Japan



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