Thallium(I) 2-Methyl-2-propanethiolate

t-BuSTl

[56393-79-4]  · C4H9STl  · Thallium(I) 2-Methyl-2-propanethiolate  · (MW 293.58)

(nucleophile; reagent for preparation of thiol esters)

Physical Data: mp 170-175 °C (dec).

Solubility: sol organic solvents.

Form Supplied in: bright yellow solid. Drying: can be dried under vacuum.

Preparative Methods: can be readily prepared starting from t-butyl thiol and thallium(I) ethoxide.1

Handling, Storage, and Precautions: the compound should be stored in a dark bottle under argon. All thallium compounds are extremely toxic to inhalation, skin contact, and ingestion. Toxicity is cumulative. Extreme caution should be used when handling these materials. Use in a fume hood.

General Discussion.

Thallium 2-methyl-2-propanethiolate is a convenient nucleophile for the preparation of thiol esters.2 The thiol esters can be prepared starting from either acid chlorides (eq 1) or diethyl phosphates (eqs 2 and 3) and t-BuSTl.3 The reaction conditions are simple, proceed in good yields, and the workup procedure is straightforward.

Due to the thermal instability of the diethyl phosphates, the preparation of thiol esters from this starting material is most efficient with thallium thiolates. Reactions with sodium and potassium thiolates in place of thallium give unsatisfactory results. The superiority of thallium thiolates can be attributed to their ease of preparation and solubility in aprotic solvents.

Thallium 2-methyl-2-propanethiolate can also be used for the formation of metal-sulfur bonds.1b,4 An example of this type of transformation in the formation of a tungsten-sulfur bond is shown in eq 4.

Related Reagents.

Thallium(I) 1-Propanethiolate.


1. (a) Spessard, G. O.; Chan, W. T.; Masamune, S. OS 1983, 61, 134. (b) Carlton, L.; Davidson, J. L. JCS(D) 1987, 895.
2. For alternative methods of thiol ester synthesis, see: Greene, T. W.; Wuts, P. G. M. Protective Groups in Organic Synthesis, 2nd ed.; Wiley: New York, 1991; p 263.
3. (a) Spessard, G. O.; Chan, W. T.; Masamune, S. OS 1983, 61, 134. (b) Masamune, S.; Kamata, S.; Diakur, J.; Sugihara, Y.; Bates, G. S. CJC 1975, 53, 3693. (c) Masamune, S.; Yamamoto, H.; Kamata, S.; Fukuzawa, A. JACS 1975, 97, 3513. (d) Masamune, S.; Kamata, S.; Schilling, W. JACS 1975, 97, 3515.
4. Davidson, J. L.; Sence, F. JOM 1991, 409, 219.

Mukund P. Sibi

North Dakota State University, Fargo, ND, USA

Nancy E. Carpenter

University of Minnesota, Morris, MN, USA



Copyright 1995-2000 by John Wiley & Sons, Ltd. All rights reserved.