Trifluoromethane sulfonate esters

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... 

Table 18 9. Macrocation f Macroester Equilibria for the Polymerization of Tetrahydrofuran at 17° C Initiated by Ethyl Trifluoromethane Sulfonate Ester...

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)... 

A reaction which is related to hydroxy-de-diazoniations is the formation of aryl trifluoromethylsulfonic esters (aryl triflates, ArOSC CFs) which became widely used reagents because of their leaving-group properties. The classical method of synthesis by esterification of phenols with trifluoromethane-sulfonic anhydride or -sulfonyl halide is, however, not applicable for the preparation of aryl triflates bearing a (free)... 

Polymerization Equilibria. As mentioned earlier, esters of strong acids, e.g. trifluoromethane sulfonic acid ("triflates"), are excellent initiators for the polymerization of THF. With such initiators, however, a complication arises. In addition to the normal propagation i depropagation equilibria of oxonium ions, Smith and Hubin postulated that the macroion ( ) may also convert into a corresponding nonpolar macroester ( ) by attack of the anion (14). ... 

Anhydrides of strong i x)tonic acids provide a group of initiators able to give dicationically terminated macromolecules °° The anhydride of trifluoromethane-sulfonic acid (triflic anhydride) initiates the polymerization of THF in this way both reactions, with rate constants ki and kai, are faster than the formation of the alkyltetrahydrofuranium cation with the corresponding triflic acid ester ... 

Pyruvate ketals can be synthesized [161] by direct condensation of a pyruvate ester with a diol in the presence of a Lewis acid, but this is less preferred because of the electron-withdrawing effect of the adjacent carboxylate group [162,163]. Therefore, several indirect methods for the acetalization have been introduced including condensation with pyruvate derivatives [164,165] or generation of the carboxylate group by oxidation of a suitable precursor [166,167,168,169]. A more efficient route to pyruvic acid acetals starts from silylated diols [170] or by the reaction between diols and methyl pyruvate dialkyl dithioacetal [171,172] activated by methyl triflate, dimethyl(methylthio)sulfonium trifluoromethane sulfonate (DMTST), nitroso tetraflu-oroborate (NOBF4), S02Cl2-trifluoromethanesulfonic acid, or Al-Iodosuccinimide (NIS) and trifluoromethanesulfonic acid [173] (O Scheme 24). 

Alternatively, halide-free 1,3-dialkylimidazolium ILs can be prepared from the five-component reaction (glyoxal, formaldehyde, two different amines and acids. Scheme 2), and those containing alkyl sulfate or trifluoromethane sulfonate anions by simple alkylation of 1-alkylimidazole with the corresponding dialkylsulfate or alkyltrifluoro-methane sulfonate ester, respectively. " ... 

Methanesulfonic acid, trifluoro-, methyl ester. See Methyl trifluoromethane sulfonate Methane, sulfonylbis-. See Dimethyl sulfone Methane, sulfonylbis trichloro-. See Bis (trichloromethyl) sulfone Methanesulfonyl chloride CAS 124-63-0 EINECS/ELINCS 204-706-1... 

See Methyl trifluoromethane sulfonate Trifluoromethanesulfonic acid triisopropylsilyl ester. See Triisopropylsilyl trifluoromethane sulfonate... 

Triisopropylsilyl chloride. See Triisopropylchlorosilane Triisopropylsilyl trifluoromethane sulfonate CAS 80522-42-5 Synonyms TIPS triflate Trifluoromethanesulfonic acid triisopropylsilyl ester... 

Trimethyls lyl triflate. See Trimethylsilyl trifluoromethane sulfonate Trimethylsilyl trifluoromethane sulfonate CAS 27607-77-8 EINECS/ELINCS 248-565-4 Synonyms Trifluoromethanesulfonic acid trimethylsilyl ester Trimethylsilyl triflate Trimethylsilyl trifluoromethyl sulfonate Classification Silane Empirical C4HgF303SSi Formula CF3S03Si(CH3)3... 

The triflate group (CF3SO3-) is reported to be the most active leaving group of the common sulfonate esters. This moiety is conveniently introduced using trifluoromethane-sulfonylimidazole, a stable, low boiling liquid. ... 

The desired sulfonate ester is usually prepared by reaction of the alcohol in pyridine with the appropriate sulfonyl chloride, that is, methanesulfonyl chloride (mesyl chloride) for a mesylate, y)-toluenesulfonyl chloride (tosyl chloride) for a tosylate, or trifluoromethane-sulfonyl chloride [or trifluoromethanesulfonic anhydride (triflic anhydride)] for a triflate. Pyridine (C5H5N, pyr) serves as the solvent and to neutralize the HCI formed. Ethanol, for example, reacts with methanesulfonyl chloride to form ethyl methanesulfonate and with yj-toluenesulfonyl chloride to form ethyl /-toluenesulfonate ... 

Further, other esters, such as those formed from alcohols with trifluoromethane-sulfonic acid (CF3SO3H) (e.g., Equation 8.24), methanesulfonic acid (CH3SO3H), (e.g., Scheme 8.21), and, in particular, toluenesulfonic acid (Scheme 8.68) are even more commonly used. Indeed, the toluenesulfonate ( tosylate ) ester is often employed since it is usually stable enough to be isolated and purified (at low temperature) but will undergo elimination to alkene and toluenesulfonic acid as the temperature is raised. 

Trifluoromethane sulfonic acid, 3-hydroxy-4-(methoxyacetyl)phenyl ester) (Chem. Abstr., Formula Index Vol. 141, 2004, 1496F)... 

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