Reaction Steps
(±)-1-(5-Chloro-2-cyclopropyl-2H-indazol-7-yl)ethyl 2,2,2-trichloroacetimidate (365 mg, 0.96 mmol) and tert-butyl 4-(4-fluorophenyl)-4-(hydroxymethyl)piperidine-1-carboxylate (366 mg, 1.05 mmol) were combined in a dichloromethane/cyclohexane mixture (1:1, 10 mL) and cooled to 0° C. The reaction was treated with tetrafluoroboric acid-diethyl ether complex (26 μL, 0.19 mmol), stirred at 0° C. for 1 h, quenched by addition of saturated sodium bicarbonate and diluted with diethyl ether. The layers were separated. The ethereal was washed with water (2×), brine (2×), dried over sodium sulfate, and concentrated. Column chromatography on silica gel (18% ethyl acetate/hexanes) gave 0.32 g (62%) as an oil. 1H-NMR (CDCl3, 500 MHz) δ 7.86 (s, 1H), 7.40 (m, 1H), 7.28-7.31 (m, 2H), 6.99-7.03 (m, 2H), 6.75 (m, 1H), 4.90 (q, J=6.4 Hz, 1H), 3.86-3.90(m, 2H), 3.32-3.36 (m, 2H), 3.00-3.09 (m, 2H), 2.04-2.17 (m, 2H), 1.84-1.95 (m, 2H), 1.43 (s, 9H), 1.41 (d, J=6.4 Hz, 3H), 1.26-1.30 (m, 2H), 1.12-1.16 (m, 2H); 13C-NMR (CDCl3, 126 MHz) δ 163.7, 161.4 (d, J=244.7 Hz), 152.2, 145.3, 138.9, 135.1, 128.9, 127.7, 122.3, 117.2, 115.2, 115.1, 79.5, 77.8, 73.9, 60.5, 41.3, 34.7, 28.6, 22.7, 14.3, 7.4. Mass spec.: 528.62 (MH)+.
