Trifluoromethane sulfonates

The silver fluorocomplexes, ie, silver hexafluoroantimonate [26042-64-8], AgSbF silver hexafluorophosphate [26042-63-7], AgPF silver tetrafluoroborate [14104-20-2], AgBF and other salts such as silver trifluoromethane sulfonate [2923-28-6], CF SO Ag, and silver trifluoroacetate [2966-50-9], CF COOAg, play an important role in the synthesis of organic compounds and have gained potential industrial importance. 

Ca.ta.lysis by Protons. The discovery of hydrogen peroxide hydroxylation of phenol in the presence of strong acids such as perchloric, trifluoromethane-sulfonic, or sulfuric acids allows suppression of all previous drawbacks of the process (18,19). This mode of hydroxylation gives high yields (85% based on H2O2 at phenol conversion of 5—6%). It can be mn without solvents and does not generate resorcinol. Its main advantage rehes on... 

In contrast to phosphorus esters, sulfur esters are usually cleaved at the carbon-oxygen bond with carbon-fluorine bond formation Cleavage of esteri nf methanesulfonic acid, p-toluenesidfonic acid, and especially trifluoromethane-sulfonic acid (tnflic acid) by fluoride ion is the most widely used method for the conversion of hydroxy compounds to fluoro derivatives Potassium fluoride, triethylamine trihydrofluoride, and tetrabutylammonium fluoride are common sources of the fluoride ion For the cleavage of a variety of alkyl mesylates and tosylates with potassium fluoride, polyethylene glycol 400 is a solvent of choice, the yields are limited by solvolysis of the leaving group by the solvent, but this phenomenon is controlled by bulky substituents, either in the sulfonic acid part or in the alcohol part of the ester [42] (equation 29)... 

An example of cleavage ol the sulfur-oxygen bond in trifluoromethane-sulfonic ester has been reported Tnfluororaethyl triflate reacts with neutral or anionic nucleophiles with elimination of carbonyl difluoride and formation of trifluoromethanesulfonyl fluoride [57] (equation 32) The mechanism of this reaction involves elimination of fluoride ion, which is a chain carrier in the substitution of fluorine for the trifluoromethoxy group... 

Thermal cleavage of boron tris(trifluoromethane)sulfonate and boron tris(pen-tafluoroethane)sulfonate was studied. Careful identificadon of the products has led to the proposal of a mechanism and an account for this process [121] (equation 93). 

Anions are just as varied as the cations, and more than 250 different ionic liquids with different anion/cation combinations are commercially available. Hexafluorophosphate, tetrafluoroborate, alkyl sulfates, trifluoromethane-sulfonates (Inflates), and halides are some anion possibilities. 

Triflucrcrrsethanesuifonate, FNHj FjCSOj, mp subl CA Registry No 42138-65-5. It is prepd by the reaction of N-fluorourethane with trifluoromethanesulfonic acid in methyl chloride (Ref 6). It is more stable than the salts listed above (Ref 6), and upon subln at low press, it dissociates into fluoramine and trifluoromethane-sulfonic acid without further decompn (Ref 7) Refs 1)0. Ruff L. Staub, ZAnorgChem 198, 32 (1931) CA 25, 5105 (1931) 2) O. Ruff... 

The aqueous aza-Diels-Alder reaction of an aldehyde and an amine hydrochloride with a diene is catalyzed by lanthanide(III) trifluoromethane sulfonates (Ln(OTf)3, triflates [24]). Some examples are reported in Schemes 6.12 and 6.13. With respect to uncatalyzed reactions, the lanthanide catalyst allows milder reaction conditions, increases the reaction yield and does not affect the diaster-eoselectivity of the reaction, but influences the regiochemistry as in the cycloaddition of 25 with 1,3-dimethyl-1,3-butadiene (Schemes 6.10 and 6.12). These results have been applied [24b-d] to the synthesis of azasugars (Scheme 6.14). 

Bruce, D.W. and Hudson, S.A. (1994) Mesomorphic complexes of silver trifluoromethane sulfonate and silver dodecylsulfate with 2- and 3-fluoro-4-alkoxy-4-stilbazoles. Journal of Materials Chemistry, 4, 479-486. 

Silica sol-gel inunobihzed La(OTf)3 (Scheme 48.2B) previously used in the acylation of a series of alcohols and activated aromatic compounds using acetic anhydride as acylating agent, showed a poor activity compared with other various sihca sol-gel inunobihzed triflate derivatives (tert-butyl-dimethylsilyl-trifluoromethane-sulfonate (BDMST), or trifhc acid (HOTf)). Acylation at the aromatic ring occurred over the BDMST and HOTf catalysts, while the La(OTl)3 catalysts only led to O-acetylated products [22]. Such behavior is characteristic... 

For conversion of the more reactive l-arylsulfonyl-3-methylimidazolium triflate (trifluoromethane sulfonate) with alcohols or phenols, no base is required 175... 

Such a methodology is also useful for the chemoselective functionalization of internal voids of dendrimers. This can be accomplished for example by adding 2 equiv. of allyl, propargyl or phosphonate trifluoromethane sulfonate on the dendrimer of generation 1 71-lGj] (Scheme 34). Functionalization occurs on the sulfur atom of the two P=N-P(S) units with the quantitative formation of the... 

Scheme 20. Reaction of 1 with trifluoromethane sulfonic acid.

The same authors studied the CL of 4,4,-[oxalylbis(trifluoromethylsulfo-nyl)imino]to[4-methylmorphilinium trifluoromethane sulfonate] (METQ) with hydrogen peroxide and a fluorophor in the presence of a, p, y, and heptakis 2,6-di-O-methyl P-cyclodextrin [66], The fluorophors studied were rhodamine B (RH B), 8-aniline-l-naphthalene sulfonic acid (ANS), potassium 2-p-toluidinylnaph-thalene-6-sulfonate (TNS), and fluorescein. It was found that TNS, ANS, and fluorescein show CL intensity enhancement in all cyclodextrins, while the CL of rhodamine B is enhanced in a- and y-cyclodextrin and reduced in P-cyclodextrin medium. The enhancement factors were found in the range of 1.4 for rhodamine B in a-cyclodextrin and 300 for TNS in heptakis 2,6-di-O-methyl P-cyclodextrin. The authors conclude that this enhancement could be attributed to increases in reaction rate, excitation efficiency, and fluorescence efficiency of the emitting species. Inclusion of a reaction intermediate and fluorophore in the cyclodextrin cavity is proposed as one possible mechanism for the observed enhancement. 

T. Akiyama, J. Iwai, Scandium Trifluoromethane-sulfonate-Catalyzed Chemoselective Allylation Reactions of Carbonyl Compounds with Tetraallylgermane in Aqueous Media Tetrahedron Lett. 1997,38, 853-856. 

The intramolecular [2+3] cycloaddition of in situ generated azides to iV-methylnitrilium ions has also been used for the preparation of tetrazolium salts. With exclusion of moisture, treatment of 4-azidobutanenitrile 64 with methyl triflate in boiling 1,2-dichloroethane affords 1-methyl-6,7-dihydro-57/-pyrrolo[l,2-< ]tetrazolium trifluoromethane sulfonate 65 in 68% yield (Scheme 6) <1997MI671>. 

Sulfenoetherification. The reagent in combination with trifluoromethane-sulfonic acid converts suitably unsaturated alcohols into five- to seven-membered cyclic ethers. The cyclization is considered to involve an intermediate episulfonium ion. 

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