Dibutyl Telluride1

(R = n-Bu)

[38788-38-4]  · C8H18Te  · Dibutyl Telluride  · (MW 241.83) (R = i-Bu)


(nucleophilic agent for the synthesis of telluronium salts, which undergo many transformations;2 used as a halophilic3 and reducing4 reagent)

Physical Data: n-Bu2Te bp 75-76 °C/4 mmHg; i-Bu2Te bp 68-70 °C/6 mmHg.

Solubility: insol H2O, ethanol; sol ether, petroleum ether, THF, etc.

Preparative Methods: dibutyl telluride and diisobutyl telluride are prepared from n-butyl bromide and isobutyl bromide with Sodium Telluride, which is prepared in situ from Tellurium powder, rongalite (Sodium Hydroxymethanesulfinate), and Sodium Hydroxide in H2O.5

Handling, Storage, and Precautions: stored and handled under N2. Care should be taken in handling Bu2Te and i-Bu2Te; because of their bad smell, experiments should be carried out in an efficient fume hood.

Organotelluronium Salts.

The reaction of dibutyl telluride or diisobutyl telluride with halides affords telluronium salts, which can mediate the syntheses of alcohols, alkenes, epoxides, and cyclopropanes.

Formation of Alcohols.

Treatment of the telluronium salts with an alkyl- or aryllithium reagent results in a lithium-tellurium exchange reaction via an unstable transient tetraorganyltellurium intermediate. The in situ generated lithium species react with carbonyl compounds to give various alcohols in high yields. In this way, homobenzylic alcohols,6 b-hydroxy nitriles,7 and (trimethylsilyl)propargyl alcohols8 are synthesized in excellent yields (eq 1-3).

Formation of Alkenes via Telluronium Ylides.

Stabilized telluronium ylides, formed from telluronium salts with Potassium t-Butoxide, react with carbonyl compounds to give a,b-unsaturated esters,9 carboxamides,10 ketones, and nitriles11 in high yields (eq 4).

Due to the ease of conversion of dibutyl telluride to the telluronium salts, these alkenation reactions can be carried out at rt in a one-pot procedure. Thus a,b-unsaturated carboxylic acid amides can be obtained in excellent yields with high (E) stereoselectivity.12 The dibutyl telluroxide formed during the reaction can be reduced back to dibutyl telluride by Triphenyl Phosphite. Thus alkenes can be obtained using a catalytic amount of dibutyl telluride (eq 5).13

Dibutyl or diisobutyl telluride reacts with carbenes or nitrenes to form telluronium ylides or tellurimides, which react with carbonyl compounds to afford alkenes or N-tosylimines (eqs 6 and 7).14,15

Formation of Epoxides via Telluronium Ylides.

Diisobutyltelluronium allylide, generated from allyldiisobutyltelluronium bromide, reacts with aldehydes to give vinyl epoxides in good yields.16 In the presence of Cesium Carbonate the epoxidation reaction can be promoted by a catalytic amount of diisobutyl telluride (eq 8).17 Allyl18 and propargyl8,18 telluronium ylides can also be formed by deprotonation with Lithium 2,2,6,6-Tetramethylpiperidide (eq 9), giving high cis selectivity in some cases.

Formation of Cyclopropane Derivatives via Telluronium Ylides.

Trimethylsilylated diisobutyltelluronium allylide reacts with a,b-unsaturated esters to afford trimethylsilylvinylcyclopropane derivatives via Michael addition in excellent yields with high stereoselectivity (eq 10).19,20

Halophilic Reactions of Dibutyl Telluride.

Owing to the great halophilicity of dibutyl telluride, several alkenation reactions have been developed. Thus in the presence of dibutyl telluride, (iodomethyl)triphenylphosphonium iodide reacts with aldehydes to afford the methylenation products (eq 11).3 A one-pot reaction of a-halo esters, malonic esters, nitriles, and ketones with aldehydes gives a,b-unsaturated esters, nitriles, and ketones in high yields (eq 12).11,21-23 A similar reaction of Diethyl Dibromomalonate with electron-deficient alkenes affords cyclopropanation products (eq 13).23

Reducing Agent.

Diisobutyl telluride reduces Titanium(IV) Chloride to Titanium(III) Chloride, which can mediate pinacolizations, carbonyl reductions, and reductive aromatization (eq 14).4

Related Reagents.

Tri-n-butylstibine; Triphenylphosphine.

1. (a) Irgolic, K. J. The Organic Chemistry of Tellurium; Gordon and Breach: New York, 1974. (b) Uemura, S. Kagaku 1981, 36, 381. (c) Engman, L. ACR 1985, 18, 274. (d) Petragnani, N.; Comasseto, J. V. S 1986, 1. (e) Back, T. G. The Chemistry of Organic Selenium and Tellurium Compounds; Patai, S., Ed.; Wiley: Chichester, 1987; p 2. (f) Engman, L. PS 1988, 38, 105. (g) Petragnani, N.; Comasseto, J. V. S 1991, 793, 897.
2. Fu, G. X.; Zhou, Z. L.; Yu, L.; Huang, Y. Z. Org. Mass Spectrom. 1992, 27, 695.
3. Li, S. W.; Huang, Y. Z.; Shi, L. L. CB 1990, 123, 1441.
4. Suzuki, H.; Manabe, H.; Enokiya, R.; Hanazaki, Y. CL 1986, 1339.
5. Balfe, M. P.; Chaplin, C. A.; Phillips, H. JCS 1938, 341.
6. Li, S. W.; Zhou, Z. L.; Huang, Y. Z.; Shi, L. L. JCS(P1) 1991, 1099.
7. Zhou, Z. L.; Shi, L. L.; Huang, Y. Z. JCS(P1) 1991, 1931.
8. Zhou, Z. L.; Huang, Y. Z.; Shi, L. L.; Hu, J. JOC 1992, 57, 6598.
9. Osuka, A.; Mori, Y.; Shimizu, H.; Suzuki, H. TL 1983, 24, 2599.
10. Osuka, A.; Hanasaki, Y.; Suzuki, H. Nippon Kagaku Kaishi 1987, 1505.
11. Huang, X.; Xie, L. H.; Wu, H. JOC 1988, 53, 4862.
12. Xiao, W. J.; Shi, L. L.; Chen, Z. Q.; Huang, Y. Z.; Lang, S. A. HC 1990, 1, 245.
13. Huang, Y. Z.; Shi, L. L.; Li, S. W.; Wen, X. Q. JCS(P1) 1989, 2397.
14. Zhou, Z. L.; Huang, Y. Z.; Shi, L. L. T 1993, 49, 6821.
15. Suzuki, H.; Takeda, S.; Hanazaki, Y. CL 1985, 679.
16. Zhou, Z. L.; Sun, Y. S.; Shi, L. L.; Huang, Y. Z. CC 1990, 1439.
17. Zhou, Z. L.; Huang, Y. Z.; Shi, L. L. TL 1992, 33, 5827.
18. Zhou, Z. L.; Huang, Y. Z.; Shi, L. L. CC 1992, 986.
19. Huang, Y. Z.; Tang, Y.; Zhou, Z. L.; Huang, J. L. CC 1993, 7.
20. Huang, Y. Z.; Tang, Y.; Zhou, Z. L.; Xia, W.; Shi, L. P. JCS(P1) 1994, 893.
21. Huang, X.; Xie, L. H.; Wu, H. TL 1987, 28, 801.
22. Zhou, Z. L.; Shi, L. L.; Huang, Y. Z. SC 1991, 21, 1027.
23. Matsuki, T.; Hu, N. X.; Aso, Y.; Otsubo, T.; Ogura, F. BCJ 1989, 62, 2105.

Yao-Zeng Huang, Zhang-Lin Zhou, & Li-Lan Shi

Shanghai Institute of Organic Chemistry, China

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