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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
PubChem CID
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.