Dimethyl Sulfoxide → (2S)-1-tert-butoxycarbonyl-2-phenylpiperidin-3-one

Participants

Reaction Conditions

Reaction Steps

Dimethyl sulfoxide (20.80 ml, 22.90 g, 29.3 mmol) in dichloromethane (75 ml) was added dropwise to a cooled (-70° C.) solution of oxalyl chloride (13.95 ml, 20.30 g, 160 mmol) in dichloromethane (350 ml). The mixture was stirred at -70° C. for 15 minutes, then (2S,3S)-1-tert-butoxycarbonyl-3-hydroxy-2-phenylpiperidine (prepared by the method described in European Patent Specification number 0 528 495-A; 36.91 g, 133 mmol) in dichloromethane (150 ml) was added dropwise. The mixture was stirred at -70° C. for 20 minutes, then allowed to warm to -30° C. The mixture was cooled to -50° C. and triethylamine (55.95 ml, 40.45 g, 400 mmol) was added slowly. The mixture was allowed to warm to 0° C. and diluted with ice-cooled dichloromethane (250 ml). The mixture was washed with ice cold aqueous citric acid solution (5%, 2×300 ml) and water (300 ml), dried (MgSO4), and the solvent was evaporated under reduced pressure to give the title compound as a yellow oil (42.3 g), which was used immediately without further purification. 1H NMR (250 MHz, CDCl3) δ7.5-7.3 (5 H, m), 5.8 (1 H, br s), 4.2 (1 H, br s), 3.4 (1 H, m), 2.6 (2 H, m), 2.0 (2 H, m), and 1.54 (9 H, s).

Provenance & Evidence