Trimethylsilyl trifluoromethanesulfonate
Names
Preferred IUPAC name
Trimethylsilyl trifluoromethanesulfonate
Other names
TMSOTf
Trimethylsilyl triflate
TMS triflate
Trifluoromethanesulfonic acid trimethylsilyl ester
Identifiers
3D model (JSmol)
ECHA InfoCard 100.044.136 Edit this at Wikidata
UNII
  • C[Si](C)(C)OS(=O)(=O)C(F)(F)F
Properties
C4H9F3O3SSi
Molar mass 222.25 g·mol−1
Appearance Colorless liquid
Density 1.225 g/mL
Boiling point 140 °C (284 °F; 413 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Trimethylsilyl trifluoromethanesulfonate (TMSOTf) is an organosilicon compound with the formula (CH3)3SiO3SCF3. It is a colorless moisture-sensitive liquid. It is the trifluoromethanesulfonate derivative of trimethylsilyl.[1] It is mainly used to activate ketones and aldehydes in organic synthesis.

Reactions

TMSOTf is quite sensitive toward hydrolysis:

(CH3)3SiO3SCF3 + H2O → (CH3)3SiOH + HO3SCF3

It is far more electrophilic than trimethylsilyl chloride.

Related to its tendency to hydrolyze, tmsOTf is effective for silylation of alcohols:[2]

(CH3)3SiO3SCF3 + ROH + Et3N → ROSi(CH3)3Si + [Et3NH]O3SCF3

A common use of (CH3)3SiO3SCF3 is for the preparation of silyl enol ethers.[3][4] One example involves the synthesis of the silyl enol ether of camphor:

It was also used in Takahashi Taxol total synthesis and in chemical glycosylation reactions.[5]

Trimethylsilyl trifluoromethanesulfonate has a variety of other specialized uses. It has been use to install tert-alkyl groups on phosphine (R = alkyl):[6]

PH3 + R3C–OAc + Me3SiOTf → [(R3C)2PH2]OTf

Deprotection of Boc-protected amines can be achieved using trimethylsilyl trifluoromethanesulfonate and triethylamine or 2,6-lutidine.[7][8]

TMSOTf is also a useful reagent to replace metal-halogen bonds with a covalent M-O(SO2CF3) bond, the by-product being the highly volatile TMSCl which is easily removed.

References

  1. ^ Joseph Sweeney; Gemma Perkins; Enrique Aguilar; Manuel A. Fernández-Rodríguez; Rodolfo Marquez; Eric Amigues; Ricardo Lopez-Gonzalez (2018). "Trimethylsilyl Trifluoromethanesulfonate". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rt338. ISBN 978-0-471-93623-7.
  2. ^ Boeckman, Robert; Tusch, Douglas J.; Biegasiewicz, Kyle F. (2015). "(S)-1,1-Diphenylprolinol Trimethylsilyl Ether". Organic Syntheses. 92: 309–319. doi:10.15227/orgsyn.092.0309.
  3. ^ Umemoto, Teruo; Tomita, Kyoichi; Kawada, Kosuke (1990). "N-Fluoropyridinium Triflate: An Electrophilic Fluorinating Agent". Organic Syntheses. 69: 129. doi:10.15227/orgsyn.069.0129.
  4. ^ Efficient Stereoselective Synthesis of Proanthocyanidin Trimers with TMSOTf-Catalyzed Intermolecular Condensation. Akiko Saito, Akira Tanaka, Makoto Ubukata and Noriyuki Nakajima, Synlett, 2004, volume 6, pages 1069-1073, doi:10.1055/s-2004-822905
  5. ^ Love, Kerry R.; Seeberger, Peter H. (2005). "Synthesis and Use of Glycosyl Phosphates as Glycosyl Donors". Organic Syntheses. 81: 225. doi:10.15227/orgsyn.081.0225.
  6. ^ Barber, Thomas; Argent, Stephen P.; Ball, Liam T. (2020-05-15). "Expanding Ligand Space: Preparation, Characterization, and Synthetic Applications of Air-Stable, Odorless Di- tert -alkylphosphine Surrogates". ACS Catalysis. 10 (10): 5454–5461. doi:10.1021/acscatal.0c01414. ISSN 2155-5435. S2CID 219017552.
  7. ^ Kuehne, Martin E.; Xu, Feng (1 December 1998). "Syntheses of Strychnan- and Aspidospermatan-Type Alkaloids. 10. An Enantioselective Synthesis of (−)-Strychnine through the Wieland−Gumlich Aldehyde". The Journal of Organic Chemistry. 63 (25): 9427–9433. doi:10.1021/jo9813989.
  8. ^ Doi, Takayuki; Numajiri, Yoshitaka; Munakata, Asami; Takahashi, Takashi (1 February 2006). "Total Synthesis of Apratoxin A". Organic Letters. 8 (3): 531–534. doi:10.1021/ol052907d. PMID 16435877.
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