(Trimethylsilyl)methanesulfonyl Chloride-Cesium Fluoride

(Me3SiCH2SO2Cl)

[18143-34-5]  · C4H11ClO2SSi  · (Trimethylsilyl)methanesulfonyl Chloride-Cesium Fluoride  · (MW 186.76) (CsF)

[13400-13-0]  · CsF  · (Trimethylsilyl)methanesulfonyl Chloride-Cesium Fluoride  · (MW 151.91)

(source of free sulfene in solution;1 source of silylated sulfene8)

Physical Data: Me3SiCH2SO2Cl is a colorless liquid, bp 50-52 °C/0.6 mmHg, 57 °C/1 mmHg; mp 18 °C, n20D 1.4700,3 1.4680.7a See also Cesium Fluoride.

Solubility: acetonitrile is the preferred solvent due to solubility of CsF and absence of hydrogen bonding; Me3SiCH2SO2Cl is soluble in most organic solvents.

Preparative Methods: Me3SiCH2SO2Cl is: (1) formed in 58% isolated yield via reaction of (Chloromethyl)trimethylsilane with Thiourea in ethanol followed by concentration and chlorination in water, extraction, and distillation;2 (2) formed in 63% isolated yield by Peracetic Acid oxidation of (trimethylsilyl)methanethiol followed by treatment with Phosphorus(V) Chloride;2 (3) formed in 84% yield through reaction of Me3SiCH2Cl with Magnesium followed by sequential reaction of the Grignard reagent with Sulfur Dioxide followed by Chlorine;3 and (4) formed in 53% yield through reaction of tetramethylsilane with Sulfuryl Chloride.7a

Handling, Storage, and Precautions: like most sulfonyl chlorides, the title compound hydrolyzes slowly to produce HCl and therefore should be kept dry. The byproduct of hydrolysis is hexamethyldisiloxane. Hydrolysis is very rapid with 5% NaOH solution.7a

Formation of Sulfene Adducts.

A widely used procedure for the generation of sulfene involves the treatment of Methanesulfonyl Chloride with Triethylamine. While adducts of sulfene, generated by this route, can usually be isolated in satisfactory yield, the amine or its acid salt may isomerize or decompose base- or acid-sensitive reaction partners. Furthermore, the interpretation of reaction mechanisms can sometimes be complicated by the presence of the amine. Thus the amine may form a complex with sulfene prior to its reaction with other substrates. In the presence of a fluoride ion source such as CsF, Me3SiCH2SO2Cl undergoes fluorodesilylation to give sulfene which can be trapped with Cyclopentadiene giving the Diels-Alder adduct 2-thiabicyclo[2.2.1]hept-5-ene 2,2-dioxide in 69% yield (eq 1). The same reaction fails when mesyl chloride-triethylamine is used as a sulfene source. Additional examples of sulfene adducts, including a number of thietane S,S-dioxides, formed from Me3SiCH2SO2Cl are given in Table 1.1,2,5,8 This procedure can also be used with homologs of Me3SiCH2SO2Cl such as Me3SiCHRSO2Cl, (Me3SiCH2SO2)2O, (Me3SiCHRSO2)2O, Me3SiCH2S(O)Cl,4 and 1-(trimethylsilyl)cyclopropanesulfonyl chloride.5,6 If Me3SiCH2SO2Cl is treated with triethylamine in the presence of the electron-rich alkene Ketene Diethyl Acetal, then the silylated sulfene trimethylsilylthioformaldehyde S,S-dioxide (Me3SiCH=SO2) is trapped.8 The mechanism of hydrolysis of Me3SiCH2SO2Cl in the presence of KF has been studied.3


1. Block, E.; Aslam, M. TL 1982, 23, 4203.
2. Block, E.; Wall, A. JOC 1987, 52, 809.
3. King, J. F.; Lam, J. Y. L. JOC 1993, 58, 3429.
4. Block, E.; Wall, A. TL 1985, 26, 1425.
5. Block, E.; Schwan, A.; Dixon, D. A. JACS 1992, 114, 3492.
6. Block, E.; Aslam, M. T 1988, 44, 281.
7. (a) Cooper, G. D. JOC 1956, 21, 1214. (b) Baukov, Y. I.; Shipov, A. G.; Gorshkova, L. V.; Savost'yanova, I. A.; Kisin, A. V. ZOB 1977, 47, 1538.
8. Shipov, A. G.; Kisin, A. V.; Baukov, Y. I. JOU 1979, 1022; Shipov, A. G.; Baukov, Y. I. JOU 1979, 1112.

Eric Block

State University of New York at Albany, NY, USA



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