Reaction Steps
To a solution of 14 (2.4 g, 10 mmol) in anhydrous DMSO (15 mL) was added NaN3 (1.0 g, 15.7 mmol). The reaction solution turned purple upon heating. After being stirred at 110° C. for 8 h, the reaction mixture was cooled to room temperature and partitioned between EtOAc (300 mL) and H2O (200 mL). The organic layer was washed with H2O (200 mL), brine (200 mL), and dried over Na2SO4. The solvents were removed by rotary evaporation. The crude product was purified by flash column chromatography (EtOAc/hexanes, 1:9) to yield azide 15 (1.7 g, 88%) as a yellow oil: 1H NMR (500 MHz, CDCl3) δ 3.60-3.75 (m, 2H), 7.00-7.15 (m, 2H), 7.15-7.35 (m, 1H), 7.40-7.60 (m, 1H); 13C NMR (125 MHz, CDCl3) δ 55.8, 56.1, 56.4, 112.95, 113.01, 113.06, 113.14, 113.19, 113.25, 117.89, 117.90, 118.06, 118.07, 118.08, 119.78, 119.81, 121.25, 121.28, 121.30, 121.33, 121.35, 121.38, 130.8, 130.9, 136.7, 161.9, 163.9; GC-MS calcd for C8H6F3N3 201. found 201. 2,2-Fifluoro-2-(3-fluorophenyl)ethanamine (4d). To a solution of 15 (2.0 g, 10.0 mmol) in EtOH (30 mL) was added 1 N HCl (15 mL) and Pd(OH)2/C (20%, 200 mg). The reaction mixture was allowed to stir under one atmosphere of H2 for 24 h. The catalyst was removed by filtration and the solvent was evaporated. The resulting yellowish solid was partitioned between diethyl ether (200 mL) and 1 N HCl (200 mL). The aqueous layer was washed with diethyl ether (200 mL) then concentrated to yield amine 4d as a white solid (1.6 g, 91%): 1H NMR (500 MHz, D2O) δ 3.60-4.66 (t, J=15.0 Hz, 2H), 7.17-7.30 (m, 3H), 7.40-7.45 (m, 1H); 13C NMR (125 MHz, D2O) δ 44.6, 44.8, 45.0, 112.6, 112.8, 118.5, 118.7, 121.3, 131.4, 131.5, 161.6, 163.6; LCQ-MS (M+H+) calcd for C8H9F3N 176. found 176; LC-TOF (M+H+) calcd for C8H9F3N 176.06816. found 176.06843.
