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27607-77-8 - Trimethylsilyl trifluoromethanesulfonate, 99% - TMS-OTf - Trifluoromethanesulfonic acid trimethylsilyl ester - A12535 - Alfa Aesar

A12535 Trimethylsilyl trifluoromethanesulfonate, 99%

CAS Number
Trifluoromethanesulfonic acid trimethylsilyl ester

Size Price ($) Quantity Availability
10g 31.72
50g 108.15
250g 444.96
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Trimethylsilyl trifluoromethanesulfonate, 99%


Chemical Properties

Formula Weight
Boiling Point
Flash Point
Refractive Index
Moisture Sensitive
Miscible with aliphatic, aromatic hydrocarbons, haloalkanes and ethers. Immiscible with water.


Trimethylsilyl trifluoromethanesulfonate is used to prepare powerful Lewis acid, difluoroboron triflate etherate in acetonitrile solvent. It is also used as a reagent in a Dieckmann-like cyclization of ester-imides and diesters. Further, it is used in the conversion of carbonyl compounds to their enol ethers. It is also employed for chemical glycosylation reactions. Its reactivity is similar to trimethylsilyl chloride and is also involved in organic synthesis.


Moisture and air sensitive. Store in a cool place. Incompatible with strong oxidizing agents and strong bases.

Literature References

Trialkylsilyl perfluoroalkanesulfonates are highly reactive silylating agents (see Appendix 4) and Lewis acids: Synthesis, 1 (1982); Adv. Silicon Chem., 1, 189 (1991).

Amides can be N,O-disilylated with TMSOTf: Org. Synth. Coll., 9, 516 (1998). For conversion of carbonyl compounds to silyl enol ethers, see, e.g.: J. Org. Chem., 58, 1449 (1993); Org. Synth. Coll., 9, 548 (1998). The reaction rate in triethylamine is almost 109 times faster than with TMS chloride: Liebigs Ann. Chem., 1718 (1980).

In general, TMSOTf has a much greater tendency to give C-silylation than TMS chloride. With esters C-silylation usually predominates: Synthesis, 867 (1977); Liebigs Ann. Chem., 816 (1983). Nitriles are C-silylated: Synthesis, 636 (1977); Synth. Commun., 18, 2111 (1988). Electron-rich alkenes, e.g. ketene acetals, as well as electron-rich aromatics such as indoles and pyrroles also undergo C-silylation: Synthesis, 928, 929 (1984):

tert-Butyl esters are cleaved directly to trimethylsilyl esters. Benzyl esters are unaffected, permitting selective cleavage: Synthesis, 545 (1980).

TMSOTf has numerous applications as a Lewis acid catalyst, notably in mediating, under very mild conditions, crossed aldol condensations between silyl enol ethers and acetals: J. Am. Chem. Soc., 102, 3248 (1980); Tetrahedron, 44, 4259 (1988); Org. Synth. Coll., 9, 642 (1998).

For a brief feature on uses of the reagent, see: Synlett, 1940 (2003).

Downey, C. W.; Poff, C. D.; Nizinski, A. N. Friedel-Crafts hydroxyalkylation of indoles mediated by trimethylsilyl trifluoromethanesulfonate. J. Org. Chem. 2015, 80 (20), 10364-10369.

Kendale, J. C.; Valentin, E. M.; Woerpel, K. A. Solvent Effects in the Nucleophilic Substitutions of Tetrahydropyran Acetals Promoted by Trimethylsilyl Trifluoromethanesulfonate: Trichloroethylene as Solvent for Stereoselective C-and O-Glycosylations. Org. Lett. 2014, 16 (14), 3684-3687.

GHS Hazard and Precautionary Statements

Hazard Statements: H314-H318-H226

Causes severe skin burns and eye damage. Causes serious eye damage. Flammable liquid and vapour.

Precautionary Statements: P210-P260-P280-P303+P361+P353-P305+P351+P338-P301+P330+P331-P304+P340-P310-P405-P501a

Keep away from heat/sparks/open flames/hot surfaces. - No smoking. Do not breathe dust/fume/gas/mist/vapours/spray. Wear protective gloves/protective clothing/eye protection/face protection. IF ON SKIN (or hair): Remove/Take off immediately all contaminated clothing. Rinse skin with water/shower. IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. IF SWALLOWED: Rinse mouth. Do NOT induce vomiting. IF INHALED: Remove to fresh air and keep at rest in a position comfortable for breathing. Immediately call a POISON CENTER or doctor/physician. Store locked up. Dispose of contents/container in accordance with local/regional/national/international regulations.

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