Anions trifluoromethanesulfonic acid, reaction with

Alkyl esters of trifluoromethanesulfonic acid, commonly called triflates, have been prepared from the silver salt and an alkyl iodide, or by reaction of the anhydride with an alcohol (18,20,21). Triflates of the 1,1-dihydroperfluoroalkanols, CF2S020CH2R can be prepared by the reaction of perfluoromethanesulfonyl fluoride with the dihydroalcohol in the presence of triethylamine (22,23). Triflates are important intermediates in synthetic chemistry. They are among the best leaving groups known, so they are commonly employed in anionic displacement reactions. 

Another approach, which permits introduction of anionic ligands of strong acids, is to react a complex containing coordinated chloride ion directly with an anhydrous strong acid, such as trifluoromethanesulfonic acid, in the total absence of any other solvent. One example, where HC1 is released as a covalent gas and leaves the anhydrous reaction mixture and the CF3SO3 anion enters the coordination sphere as an O-bound monodentate ligand, is reaction with chloropentaamminecobalt(III) chloride (6.19). 

No reaction between trimethy](trifluoroniethyl)silane and sulfur dioxide occurs in the absence of an anionic initiator when one molar equivalent of tetrabutylammonium fluoride is used, clean formation of tetrabutylammonium trifluoromethanesulfinate is observed.112 Although oxidation to the corresponding sulfonate occurred readily upon treatment with 30% hydrogen peroxide, attempts to liberate the free acid from the salt proved unsuccessful. When sodium trimethylsilanolate was used as the initiator, however, the reaction sequence was successful. The overall yield of trifluoromethanesulfonic acid (31) was about 30%. 

The reaction of [Re(Me)(NO)(PPh3)Cp] with trifluoromethanesulfonic acid (triflic acid) in dichloromethane at 0 °C results in cleavage of the Re-Me bond and formation of [Re(0S02CF3)(N0)(PPh3)Cp] by formal ion exchange of methyl anion for the triflate anion. 3,64 Methane was not detected in this reaction. However, in other protonation reactions of rhenium alkyls, [Re(R)(NO)(PPh3)Cp], formation of alkane, RH, has been confirmed.63... 

It could also be shown by Berkessel and coworkers that the ionic liquid l-n-octyl-3-methyUmidazolium bis(trifluoromethanesulfon)amide [omim] [BTA] can replace HFIP as solvent (Scheme 98) . In this reaction medium, 1-octene and vinylcyclohexane, which are generally unreactive substrates under most of the known procedures in the literature, were epoxidized by phenylarsonic acid (4%) in 6 to 6.5 hours in the presence of 50% hydrogen peroxide with yields of 68 and 80%, respectively. The [BTA] anion seems to be essential for good epoxidation results, since other ionic liquids with different anions this anion did not affect the desired conversion. For the epoxidation in HFIP a charge... 

Aside from thallation, trivalent thallium is best known as a versatile oxidant in organic chemistry many of the reactions proceed with unique rearrangements. Let us first consider one that does not involve rearrangement. Thus, thallium(III) triflate (see Section 1.14 for the structure of the triflate anion), which may be obtained from the more common thallium(III) nitrate by treatment with trifluoromethanesulfonic (triflic) acid in DMF, oxidizes acetophenone to its a-trifluoromethanesulfonyloxy derivative ... 

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