Chemistry:Trimethylsilyl trifluoromethanesulfonate

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Trimethylsilyl trifluoromethanesulfonate
TmsOTf.svg
Names
Preferred IUPAC name
Trimethylsilyl trifluoromethanesulfonate
Other names
TMSOTf
Trimethylsilyl triflate
TMS triflate
Trifluoromethanesulfonic acid trimethylsilyl ester
Identifiers
3D model (JSmol)
UNII
Properties
C4H9F3O3SSi
Molar mass 222.26 g/mol
Appearance colourless 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).
Infobox references
Tracking categories (test):

Trimethylsilyl trifluoromethanesulfonate (TMSOTf) is an organosilicon compound with the formula (CH
3
)
3
SiO
3
SCF
3
. 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:

(CH
3
)
3
SiO
3
SCF
3
+ H
2
O → (CH
3
)
3
SiOH + HO
3
SCF
3

It is far more electrophilic than trimethylsilyl chloride.

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

(CH
3
)
3
SiO
3
SCF
3
+ ROH + Et
3
N → ROSi(CH
3
)
3
Si + [Et
3
NH]O
3
SCF
3

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

Tms enol ether formation.svg

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]

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 978-0471936237. 
  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" (in en). ACS Catalysis 10 (10): 5454–5461. doi:10.1021/acscatal.0c01414. ISSN 2155-5435. https://pubs.acs.org/doi/10.1021/acscatal.0c01414. 
  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.