To a solution of N- [4-chloro-2-fluoro-3-(2-hydroxyethyl)phenyl]-2,2-difluoro-2-(4-fluoronaphthyl)acetamide (1.9 g, 4.6 mmol), as prepared in the preceding step, in THF (19 mL) at 0° C. was added dropwise a solution of BH3.THF complex (19.4 mL, 19.4 mmol, 1.0 M in THF) over a period of 20 minutes, and the reaction mixture continued to stir until the ice bath expired. The mixture was then heated at reflux in an oil bath at 75° to 80° C. for 3 hours, and continued to stir at ambient temperature overnight. A solution of NaHCO3 (1.63 g, 19.4 mmol) in H2O (20 mL) was added, the THF was evaporated, and the resulting mixture was extracted with DCM twice. The extracts were combined, washed with H2O and brine, dried over Na2SO4, concentrated, and flash chromatographed on silica gel eluting with EtOAc/DCM (0, 1, 1.5%) to give the title compound (805 mg, 44% yield) as a white solid. 1H-NMR (400 MHz, CDCl3) δ 8.24-8.19 (m, 2H), 7.70-7.61 (m, 3H), 7.14 (t, J=9.3 Hz, 1H), 6.90 (dd, J=8.7, 1.6 Hz, 1H), 6.42 (t, J=8.9 Hz, 1H), 4.22-4.16 (m, 1H), 4.00 (dt,J=13.4, 6.8 Hz, 2H), 3.82 (dd, J=12.1, 6.4 Hz, 2H), 3.02 (dt, J=6.8, 2.3 Hz, 2H), 1.39 (br s, 1H). Mass spectrum (LCMS, ESI) calc'd for C20H17ClF4NO (M+H): 398.1. Found: 398.3.
