To a solution of 4-(adamantan-1-ylmethoxy)-5-bromo-2-fluoro-N-(methylsulfonyl)benzamide (0.340 g, 0.74 mmol) in anhydrous tetrahydrofuran (5 mL) was added tert-butyllithium (1.7 M solution in pentane, 1.31 mL, 2.22 mmol) at −78° C. The reaction mixture was stirred for 30 minutes at −78° C. followed by addition of acetaldehyde (0.21 mL, 3.70 mmol). The reaction mixture was allowed to warm to ambient temperature and stirred for 16 hours. After quenched with 1 N hydrochloric acid (5 mL), the mixture was diluted with ethyl acetate (100 mL). The organic phase was washed with brine (5 mL), dried over anhydrous sodium sulfate, and filtered. Concentration of the filtrate gave a residue which was purified by reverse-phase preparative HPLC to afford the title compound as an off-white solid (0.075 g, 24%): 1H NMR (300 MHz, DMSO-d6) δ 11.79 (s, 1H), 7.60 (t, J=8.7 Hz, 1H), 6.93 (dd, J=13.0, 2.2 Hz, 1H), 6.86 (dd, J=8.7, 2.3 Hz, 1H), 5.04 (br s, 1H), 4.17-4.07 (m, 1H), 3.65-3.56 (m, 1H), 3.63 (s, 2H), 3.45 (dd, J=14.3, 5.1 Hz, 1H), 2.02-1.94 (m, 3H), 1.76-1.57 (m, 12H), 1.20 (d, J=6.3 Hz, 3H); MS (ES−) m/z 424.2 (M−1).
