Methyl trifluoromethanesulfonate

Last updated
Methyl trifluoromethanesulfonate
StructureMeOTf.svg
Methyl-triflate-3D-balls.png
Names
Preferred IUPAC name
Methyl trifluoromethanesulfonate
Other names
Trifluoromethanesulfonic acid, methyl ester
Triflic acid, methyl ester, methyl triflate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.005.793 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 206-371-7
PubChem CID
UNII
UN number 2924
  • InChI=1S/C2H3F3O3S/c1-8-9(6,7)2(3,4)5/h1H3 Yes check.svgY
    Key: OIRDBPQYVWXNSJ-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C2H3F3O3S/c1-8-9(6,7)2(3,4)5/h1H3
    Key: OIRDBPQYVWXNSJ-UHFFFAOYAL
  • COS(=O)(=O)C(F)(F)F
Properties
C2H3F3O3S
Molar mass 164.10 g·mol−1
AppearanceColourless Liquid
Density 1.496 g/mL
Melting point −64 °C (−83 °F; 209 K)
Boiling point 100 °C (212 °F; 373 K)
Hydrolyzes
Hazards [1]
Occupational safety and health (OHS/OSH):
Main hazards
Corrosive
GHS labelling:
Danger
H226, H301, H311, H314, H330
P210, P233, P303+P361+P353, P304+P340+P310, P305+P351+P338, P380
Flash point 38 °C (100 °F; 311 K)
Related compounds
Related compounds
Methyl fluorosulfonate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Methyl trifluoromethanesulfonate, also commonly called methyl triflate and abbreviated MeOTf, is the organic compound with the formula CF3SO2OCH3. It is a colourless liquid which finds use in organic chemistry as a powerful methylating agent. [2] The compound is closely related to methyl fluorosulfonate (FSO2OCH3). Although there has yet to be a reported human fatality, several cases were reported for methyl fluorosulfonate (LC50 (rat, 1 h) = 5 ppm), and methyl triflate is expected to have similar toxicity based on available evidence. [3] [ verification needed ]

Contents

Synthesis

Methyl triflate is commercially available, however it may also be prepared in the laboratory by treating dimethyl sulfate with triflic acid. [4]

CF3SO2OH + (CH3O)2SO2 → CF3SO2OCH3 + CH3OSO2OH

Reactivity

Hydrolysis

Upon contact with water, methyl triflate loses its methyl group, forming triflic acid and methanol:

CF3SO2OCH3 + H2O → CF3SO2OH + CH3OH

Methylation

One ranking of methylating agents is (CH3)3O+ > CF3SO2OCH3 ≈ FSO2OCH3 > (CH3)2SO4 > CH3I . [4] Methyl triflate will alkylate many functional groups which are very poor nucleophiles such as aldehydes, amides, and nitriles. It does not methylate benzene or the bulky 2,6-di-tert-butylpyridine. [2] Its ability to methylate N-heterocycles is exploited in certain deprotection schemes. [5]

Cationic polymerization

Methyl triflate initiates the living cationic polymerization of lactide [6] and other lactones including β-propiolactone, ε-caprolactone and glycolide. [7]

Polymerization of e-caprolactone initiated by methyl triflate Kationische Polymerisation von Caprolacton mit Methyltriflat.svg
Polymerization of ε-caprolactone initiated by methyl triflate

Cyclic carbonates like trimethylene carbonate and neopentylene carbonate (5,5-dimethyl-1,3-dioxan-2-one) can be polymerized to the corresponding polycarbonates. [8] 2-alkyl-2-oxazolines, for example 2-ethyl-2-oxazoline, are also polymerized to poly(2-alkyloxazoline)s. [9]

Applications

Radiochemistry

Carbon-11 methyl triflate ([11C]MeOTf [10] ), or methyl triflate containing the carbon-11 isotope, is commonly used in radiochemistry to synthesize radioactively labeled compounds that can be traced in living organisms using positron emission tomography (PET). For example, [11C]MeOTf has been used extensively in the production of Pittsburgh Compound B, which first allowed β-amyloid plaques to be imaged in a living brain.

See also

Related Research Articles

<span class="mw-page-title-main">Ester</span> Compound derived from an acid

In chemistry, an ester is a functional group derived from an acid in which the hydrogen atom (H) of at least one acidic hydroxyl group of that acid is replaced by an organyl group. Analogues derived from oxygen replaced by other chalcogens belong to the ester category as well. According to some authors, organyl derivatives of acidic hydrogen of other acids are esters as well, but not according to the IUPAC.

In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula CH3. In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in many organic compounds. It is a very stable group in most molecules. While the methyl group is usually part of a larger molecule, bonded to the rest of the molecule by a single covalent bond, it can be found on its own in any of three forms: methanide anion, methylium cation or methyl radical. The anion has eight valence electrons, the radical seven and the cation six. All three forms are highly reactive and rarely observed.

Lactones are cyclic carboxylic esters. They are derived from the corresponding hydroxycarboxylic acids by esterification. They can be saturated or unsaturated. Some contain heteroatoms replacing one or more carbon atoms of the ring.

In polymer chemistry, ring-opening polymerization (ROP) is a form of chain-growth polymerization in which the terminus of a polymer chain attacks cyclic monomers to form a longer polymer. The reactive center can be radical, anionic or cationic. Some cyclic monomers such as norbornene or cyclooctadiene can be polymerized to high molecular weight polymers by using metal catalysts. ROP is a versatile method for the synthesis of biopolymers.

<span class="mw-page-title-main">Sulfonate</span> Organosulfur compound of the form R–S(=O)2–O (charge –1)

In organosulfur chemistry, a sulfonate is a salt, anion or ester of a sulfonic acid. Its formula is R−S(=O)2−O, containing the functional group −S(=O)2−O, where R is typically an organyl group, amino group or a halogen atom. Sulfonates are the conjugate bases of sulfonic acids. Sulfonates are generally stable in water, non-oxidizing, and colorless. Many useful compounds and even some biochemicals feature sulfonates.

<span class="mw-page-title-main">Triflate</span> Chemical group (–OSO2CF3) or anion (charge –1)

In organic chemistry, triflate, is a functional group with the formula R−OSO2CF3 and structure R−O−S(=O)2−CF3. The triflate group is often represented by −OTf, as opposed to −Tf, which is the triflyl group, R−SO2CF3. For example, n-butyl triflate can be written as CH3CH2CH2CH2OTf.

<span class="mw-page-title-main">Sulfoxide</span> Organic compound containing a sulfinyl group (>SO)

In organic chemistry, a sulfoxide, also called a sulphoxide, is an organosulfur compound containing a sulfinyl functional group attached to two carbon atoms. It is a polar functional group. Sulfoxides are oxidized derivatives of sulfides. Examples of important sulfoxides are alliin, a precursor to the compound that gives freshly crushed garlic its aroma, and dimethyl sulfoxide (DMSO), a common solvent.

<span class="mw-page-title-main">Sulfonium</span> Cation of the form [SR3]+

In organic chemistry, a sulfonium ion, also known as sulphonium ion or sulfanium ion, is a positively-charged ion featuring three organic substituents attached to sulfur. These organosulfur compounds have the formula [SR3]+. Together with a negatively-charged counterion, they give sulfonium salts. They are typically colorless solids that are soluble in organic solvent.

<span class="mw-page-title-main">Triflic acid</span> Chemical compound

Triflic acid, the short name for trifluoromethanesulfonic acid, TFMS, TFSA, HOTf or TfOH, is a sulfonic acid with the chemical formula CF3SO3H. It is one of the strongest known acids. Triflic acid is mainly used in research as a catalyst for esterification. It is a hygroscopic, colorless, slightly viscous liquid and is soluble in polar solvents.

Lanthanide triflates are triflate salts of the lanthanides. These salts have been investigated for application in organic synthesis as Lewis acid catalysts. These catalysts function similarly to aluminium chloride or ferric chloride, but they are water-tolerant (stable in water). Commonly written as Ln(OTf)3·(H2O)9 the nine waters are bound to the lanthanide, and the triflates are counteranions, so more accurately lanthanide triflate nonahydrate is written as [Ln(H2O)9](OTf)3.

<span class="mw-page-title-main">Methyl fluorosulfonate</span> Chemical compound

Methyl fluorosulfonate, also known as magic methyl, is the organic compound with the formula FSO2OCH3. It is a colorless liquid that is used as a strong methylating agent in organic synthesis. Because of its extreme toxicity, it has largely been replaced by the related reagent methyl trifluoromethanesulfonate.

<span class="mw-page-title-main">Ethylene carbonate</span> Chemical compound

Ethylene carbonate (sometimes abbreviated EC) is the organic compound with the formula (CH2O)2CO. It is classified as the cyclic carbonate ester of ethylene glycol and carbonic acid. At room temperature (25 °C) ethylene carbonate is a transparent crystalline solid, practically odorless and colorless, and somewhat soluble in water. In the liquid state (m.p. 34-37 °C) it is a colorless odorless liquid.

<span class="mw-page-title-main">Silver trifluoromethanesulfonate</span> Chemical compound

Silver trifluoromethanesulfonate, or silver triflate is the triflate (CF3SO3) salt of Ag+. It is a white or colorless solid that is soluble in water and some organic solvents including, benzene. It is a reagent used in the synthesis of organic and inorganic triflates.

<span class="mw-page-title-main">Triflyl group</span> Chemical group (–SO2CF3)

In organic chemistry, the triflyl group is a functional group with the formula R−SO2CF3 and structure R−S(=O)2−CF3. The triflyl group is often represented by –Tf.

Living cationic polymerization is a living polymerization technique involving cationic propagating species. It enables the synthesis of very well defined polymers and of polymers with unusual architecture such as star polymers and block copolymers and living cationic polymerization is therefore as such of commercial and academic interest.

<span class="mw-page-title-main">Trimethyloxonium tetrafluoroborate</span> Chemical compound

Trimethyloxonium tetrafluoroborate is the organic compound with the formula [(CH3)3O]+[BF4]. This salt is a strong methylating agent, being a synthetic equivalent of CH+3. It is a white solid that rapidly decomposes upon exposure to atmospheric moisture, although it is robust enough to be weighed quickly without inert atmosphere protection. Triethyloxonium tetrafluoroborate is a closely related compound.

<span class="mw-page-title-main">2-Ethyl-2-oxazoline</span> Chemical compound

2-Ethyl-2-oxazoline (EtOx) is an oxazoline which is used particularly as a monomer for the cationic ring-opening polymerization to poly(2-alkyloxazoline)s. This type of polymers are under investigation as readily water-soluble and biocompatible materials for biomedical applications.

Parisa Mehrkhodavandi is a Canadian chemist and Professor of Chemistry at the University of British Columbia (UBC). Her research focuses on the design of new catalysts that can effect polymerization of sustainably sourced or biodegradable polymers.

<span class="mw-page-title-main">Hafnium trifluoromethanesulfonate</span> Chemical compound

Hafnium(IV) triflate or hafnium trifluoromethansulfonate is a salt with the formula Hf(OSO2CF3)4, also written as Hf(OTf)4. Hafnium triflate is used as an impure mixture as a catalyst. Hafnium (IV) has an ionic radius of intermediate range (Al < Ti < Hf < Zr < Sc < Ln) and has an oxophilic hard character typical of group IV metals. This solid is a stronger Lewis acid than its typical precursor hafnium tetrachloride, HfCl4, because of the strong electron-withdrawing nature of the four triflate groups, which makes it a great Lewis acid and has many uses including as a great catalyst at low Lewis acid loadings for electrophilic aromatic substitution and nucleophilic substitution reactions.

<span class="mw-page-title-main">Poly(trimethylene carbonate)</span> Polycarbonate

Poly(trimethylene carbonate) (PTMC) is an aliphatic polycarbonate synthesized from the 6-membered cyclic carbonate, trimethylene carbonate (1,3-propylene carbonate or 1,3-Dioxan-2-one). Trimethylene carbonate (TMC) is a colorless crystalline solid with melting point ranging between 45°C and 48 °C and boiling point at 255°C (at 760 mmHg). TMC is originally synthesized from 1,3-propanediol with phosgene or carbon monoxide, which are highly poisonous gases. Another route is from the transesterification of 1,3-propanediol and dialkylcarbonates. This route is considered "greener" compared to the other one, since precursors can be obtained from renewable resources and carbon dioxide.

References

  1. "Methyl trifluoromethanesulfonate". Sigma-Aldrich. Retrieved 31 October 2021.
  2. 1 2 Alder, Roger W.; Phillips, Justin G. E.; Huang Lijun; Huang Xuefei (2005). "Methyltrifluoromethanesulfonate". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rm266m.pub2. ISBN   0471936235.
  3. Alder, R. W.; Sinnott, M. L.; Whiting, M. C.; Evans, D. A. (1978). "Hazards of powerful methylating agents". Chemistry in Britain. Vol. 14, no. 7. p. 324. Miscited as (1976) Chem. Eng. News , vol. 54, no. 36, p. 56 in Alder et al. 2005
  4. 1 2 Stang, Peter J.; Hanack, Michael; Subramanian, L. R. (1982). "Perfluoroalkanesulfonic Esters: Methods of Preparation and Applications in Organic Chemistry". Synthesis. 1982 (2): 85–126. doi:10.1055/s-1982-29711. ISSN   0039-7881.
  5. Albert I. Meyers & Mark E. Flanagan (1998). "2,2′-Dimethoxy-6-formylbiphenyl". Organic Syntheses ; Collected Volumes, vol. 9, p. 258.
  6. Rangel, Irma; Ricard, Michèle; Ricard, Alain (1994). "Polymerization of L-lactide and ε-caprolactone in the presence of methyl trifluoromethanesulfonate". Macromolecular Chemistry and Physics. 195 (9): 3095–3101. doi:10.1002/macp.1994.021950908.
  7. Jonté, J. Michael; Dunsing, Ruth; Kricheldorf, Hans R. (1985). "Polylactones. 4. Cationic Polymerization of Lactones by Means of Alkylsulfonates". Journal of Macromolecular Science: Part A - Chemistry. 22 (4): 495–514. doi:10.1080/00222338508056616. ISSN   0022-233X.
  8. Kricheldorf, Hans R.; Weegen-Schulz, Bettina; Jenssen, Jörg (1998). "Cationic polymerization of aliphatic cyclocarbonates". Macromolecular Symposia. 132 (1): 421–430. doi:10.1002/masy.19981320139.
  9. Glassner, Mathias; D’hooge, Dagmar R.; Young Park, Jin; Van Steenberge, Paul H.M.; Monnery, Bryn D.; Reyniers, Marie-Françoise; Hoogenboom, Richard (2015). "Systematic investigation of alkyl sulfonate initiators for the cationic ring-opening polymerization of 2-oxazolines revealing optimal combinations of monomers and initiators". European Polymer Journal. 65: 298–304. doi:10.1016/j.eurpolymj.2015.01.019. hdl: 1854/LU-5924229 .
  10. Jewett, D. M. (1992). "A simple synthesis of [11C]methyl triflate". International Journal of Radiation Applications and Instrumentation, Part A. 43 (11): 1383–1385. doi:10.1016/0883-2889(92)90012-4. hdl: 2027.42/29777 . ISSN   0883-2889. PMID   1333459.