A solution of N-((3S,4R,5S)-3-(2-fluorophenyl)-4-(hydroxymethyl)-5-(trifluoromethyl)-tetrahydrofuran-3-ylcarbamothioyl)benzamide (258.3 g, 583.8 mmol) in CH2Cl2 (1.55 L) was cooled to −19.4° C. Pyridine (118 mL, 1.46 mol) was added while maintaining temperature at −20° C., and then the reaction mixture was cooled to −24° C. In another nitrogen purged vessel, CH2Cl2 (258 mL) was added followed by trifluoromethanesulfonic anhydride (108.0 mL, 642.2 mmol). The resulting solution was added to the reaction mixture over 30 min, while maintaining temperature <−19.7° C. Upon completed addition, the reaction mixture was stirred for 30 min at −20° C. to −15° C., and then warmed to −11° C. over 20 min. Saturated aq. NH4Cl (646 mL) and water (390 mL) was added. The mixture was warmed to ambient temperature and the aq. layer was removed. The organics were washed with premixed saturated aq. NH4Cl (646 mL) and water (390 mL). The aq. layers were combined, and extracted once with CH2Cl2 (520 mL). The organics were combined, and concentrated under vacuum to afford a light orange foam (250 g, 100%). The residue was used in the next stage without purification. 1H NMR (500 MHz, CDCl3) δ ppm 8.03 (d, J=6.7 Hz, 2H), 7.52 (t, J=7.0 Hz, 1H), 7.48-7.31 (m, 4H), 7.20 (t, J=7.4 Hz, 1H), 7.12 (dd, J=12.0, 8.4 Hz, 1H), 4.82-4.73 (m, 1H), 4.60 (d, J=8.9 Hz, 1H), 4.03 (d, J=8.3 Hz, 1H), 3.57 (d, J=2.7 Hz, 1H), 3.20 (d, J=13.6 Hz, 1H), 2.81 (dd, J=13.8, 2.5 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ ppm 171.50, 159.57 (d, JCF=247.2 Hz), 134.62, 132.49, 130.65 (d, JCF J=8.8 Hz), 129.77, 128.51, 128.45, 125.14 (q, JCF=281.8 Hz), 124.97 (d, JCF=3.0 Hz), 124.66 (d, JCF=10.3 Hz), 117.05 (d, JCF=23.5 Hz), 66.81 (d, JCF=5.2 Hz), 38.90, 23.20.
