Cyclohexene → 4-(Trifluoromethyl)-4-piperidinol

Participants

Reaction Steps

To a stirred solution of benzyl 4-hydroxy-4-(trifluoromethyl)piperidine-1-carboxylate (347 g, 1.15 mole) in EtOH (1.2 L) was added Pd—C (Degussa type, 10 wt. % Pd, 50% H2O, 26.0 g, 12.2 mmol) and cyclohexene (850 mL, 8.39 mol). The mixture was heated to a gentle reflux for 1 hour resulting in a slight exotherm and the vigorous evolution of gas. Upon cooling to ambient temperature, the mixture was filtered through Celite®, and the filtrate was concentrated. The resulting residue was dissolved in CH2Cl2 (500 mL), dried (Na2SO4), filtered, and concentrated to give an orange solid. The crude material was crystallized from MTBE to give 160 g (83%) of product as an off-white solid. 1H NMR (400 MHz, DMSO-d6) δ 5.71 (br s, 1H), 2.74 (m, 4H), 2.42 (br s, 1H, overlaps DMSO), 1.53 (m, 4H).

Provenance & Evidence