[3908-52-2]  · C4H12SSi  · (Methylthio)trimethylsilane  · (MW 120.32)

(thioacetalization under neutral conditions;1,2 cleavage of ethers3,4)

Physical Data: bp 110-114 °C; d 0.848 g cm-3.

Solubility: sol organic solvents (CH2Cl2, benzene, acetonitrile, ether).

Form Supplied in: colorless liquid; commercially available.

Preparative Method: prepared as described by Evans et al.14

Handling, Storage, and Precautions: the reagent is sensitive to moisture and incompatible with strong oxidizing agents. Should be used in a well-ventilated fume hood.

Carbonyl Protection.

The Lewis acid-catalyzed reaction of aldehydes and ketones with (methylthio)trimethylsilane gives rise to the corresponding thioacetals (eq 1).1,2 Selective thioacetalization can be achieved with this reagent (eq 2).1 The reaction with a,b-unsaturated aldehydes and ketones leads to the formation of the 1,4-addition product.

Cleavage of Acyclic and Cyclic Ethers.

Acyclic ethers are readily cleaved by (methylthio)trimethylsilane (eq 3).3 In contrast to Iodotrimethylsilane, esters are unaffected under the reaction conditions. The reagent is also compatible with acetals and amides.4 The zinc chloride-catalyzed reaction of oxetanes with (methylthio)trimethylsilane leads to the formation of ring-opened products (eq 4).5 No reaction takes place in the absence of Zinc Chloride.

Vinyl Sulfides.

A general route to vinyl sulfides has been achieved through the reaction of thiosilanes with silyl enol ethers in the presence of Boron Trifluoride Etherate (eq 5).6

Miscellaneous Transformations.

The reaction of Me3SiSMe with glycopyranoses leads to the stereoselective formation of 1-thioglycosides (eq 6).7,8 When primary nitro compounds are treated sequentially with n-Butyllithium followed by Me3SiSMe, the corresponding thiohydroximates are produced in good yields (eq 7).9 4-Sulfinylazetidin-2-ones undergo a novel substitution reaction with silylated heteronucleophiles in the presence of a catalytic amount of Zinc Iodide (eq 8).10,11 When propenoyltrimethylsilane is treated with Me3SiSMe, the synthetically useful silyl enol ethers of acylsilanes are formed (eq 9).12 Orthothioesters are formed when esters are treated with Me3SSiMe and Aluminum Chloride.13

Related Reagents.


1. Evans, D. A.; Truesdale, L. K.; Grimm, K. G.; Nesbitt, S. L. JACS 1977, 99, 5009.
2. Groutas, W. C.; Felker, D. S. S 1980, 861.
3. Hanessian, S.; Guindon, Y. TL 1980, 21, 2305.
4. Guindon, Y.; Young, R. N.; Frenette, R. SC 1981, 11, 391.
5. Firgo, H. A.; Weber, W. P. JOM 1981, 222, 201.
6. Degl'Innocenti, A.; Ulivi, P.; Capperucci, A.; Mordini, A.; Reginato, G.; Ricci, A. SL 1992, 499.
7. Pozsgay, V.; Jennings, H. J. TL 1987, 28, 1375.
8. (a) Hasegawa, A.; Ohki, H.; Nagahama, T.; Ishida, H.; Kiso, M. Carbohydr. Res. 1991, 212, 277: (b) Kameyama, A.; Ishida, H.; Kiso, M.; Hasegawa, A. Carbohydr. Res. 1990, 200, 269.
9. Hwu, J. R.; Tsay, S-C.; T 1990, 46, 7413.
10. Kita, Y.; Shibata, N.; Yoshida, N.; Tohjo, T. TL 1991, 32, 2375.
11. de Vries, J. G.; Hauser, G.; Sigmund, G. H 1985, 23, 1081.
12. Ricci, A.; Degl'Innocenti, A.; Borselli, G.; Reginato, G. TL 1987, 28, 4093.
13. Matthews, D. P.; Whitten, J. P.; McCarthy, J. R. TL 1986, 27, 4861.
14. Evans, D. A.; Grimm, E. G.; Truesdale, L. K. JACS 1975, 97, 3229.

William C. Groutas

Wichita State University, KS, USA

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