Tri fluoromethane sulfonic acid

CgHeNeOfi mw 258.18 N 32.56% OB to COj —55.78% It yel triclinic cryst mp, not fixed, however, instantaneous hot-bar decompn temp is 450—51° (thermal decompn is rapid above 320°) d 1.93 0.0/g/cc (cryst observed), 1.937 g/cc (calcd from X-ray data). > 20% wt/vol sol in superacids such as coned sulfuric acid, chlorosulfonic acid, fluorosulfonic acid and tri-fluoromethane sulfonic acid Ml.1% wt/vol sol in solvents such as aniline, dimethylformamide, phenylhydrazine, ethylenediamine, gammabutyro-lactone and NB insol in benz, chlf, ethanol, eth, and gl acetic acid (Refs 6,9,12, 34, 56 and 66). 

Treatment of sulfoxide 20 with Me2SiCl2 and alcohols a-f gave the mixed silyl acetals 21a-21f in good yields (Scheme 7). Activation of the sulfoxide with tri-fluoromethane sulfonic acid anhydride (TfjO) and base, presumably resulting in the five-membered intermediates 22a-22f responsible for exclusive glycosidation at the P face, gave P-mannopyranosides 23a-23f. 

The aldol reactions introduced thus far have been performed under basic conditions where enolate species are involved as the reactive intermediate. In contrast to the commonly accepted carbon-anion chemistry, Mukaiyama developed another practical method in which enol species can be used as the key intermediates. He is the first chemist to successfully demonstrate that acid-catalyzed aldol reactions using Lewis acid (such as TiCU) and silyl enol ether as a stable enol equivalent can work as well.17 Furthermore, he developed the boron tri-fluoromethane sulfonate (triflate)-mediated aldol reactions via the formation of formyl enol ethers. 

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