Nitrogen → Tert-butyl 4-(4-fluoro-2-(trifluoromethyl)phenyl)piperidine-1-carboxylate

Participants

Reaction Steps

A solution of tert-butyl 4-(4-fluoro-2-(tri-fluoromethyl)phenyl)-5,6-dihydropyridine-1(2H)-carboxylate (1.29 g, 3.74 mmol) in ethyl acetate (20 mL) andacetic acid (0.22 mL) was sparged with N2. Platinum dioxide (84 mg) was added and the resulting suspension was sparged with N2 for 5 min. The mixture was placed under an H2 atmosphere at 1 atm. After 18 h the reaction was sparged with N2 for 15 min, filtered through a diatomaceous earth pad, recharged with platinum dioxide (100 mg) and stirred under a 1 atm hydrogen atmosphere. The filtration and recharging of the reaction was repeated thrice over the next 64 h. The reaction was filtered through diatomaceous earth. The obtained filtrate was washed with sodium bicarbonate solution, dried (Na2SO4) and concentrated under reduced pressure. The residue was chromatographed over silica gel (Isco CombiFlash Rf unit, 24 g Redisep column, 0% to 100% EtOAc in hexanes) to provide tert-butyl 4-(4-fluoro-2-(trifluoromethyl)phenyl)piperidine-1-carboxylate as a yellow oil (0.813 g, 63%): 1H NMR (300 MHz, CDCl3) δ 7.37-7.20 (m, 3H), 4.27-4.22 (m, 2H), 3.07-2.99 (m, 1H), 2.85-2.75 (m, 2H), 2.04-1.46 (m, 13H).

Provenance & Evidence