Tetramethylene sulfoxide → 4-(2,2,2-Trifluoroethoxy)-1-naphthyl-tetrahydrothiophenium 2-benzoyloxy-1,1,3,3,3-pentafluoro-propane-1-sulfonate

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Reaction Steps

In 6 g of Eaton's reagent (Aldrich, diphosphorus pentoxide/methanesulfonic acid solution) was dispersed 2.4 g (0.0107 mol) of 1-(2,2,2-trifluoroethoxy)naphthalene in Synthesis Example 1-3. With stirring, 2.2 g (0.0214 mol) of tetramethylene sulfoxide was added dropwise to the dispersion. The solution was matured overnight at room temperature and combined with 30 g of water and 30 g of diisopropyl ether, from which a water layer was separated. The water layer was again washed with 30 g of diisopropyl ether. This aqueous solution was combined with 3.4 g (0.0095 mol) of sodium 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate synthesized in accordance with the teaching of JP-A 2007-145797, after which extraction was effected twice with 50 g of dichloromethane. The organic layer was washed with water and distilled in vacuum to remove the solvent. The residue was poured into isopropyl ether for crystallization, filtered and dried, obtaining the target compound. White crystals, 5.3 g, yield 87%.

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