Di-tert-butyl dicarbonate → Diethylamine

Participants

Reaction Steps

To a mixture of (3R,5R & 3S,5S)-3-azido-5-(2,3-difluorophenyl)-1-(2,2,2-trifluoroethyl)piperidin-2-one (6.14 g, 18.4 mmol) and di-tert-butyl dicarbonate (4.81 g, 22.0 mmol) in EtOH (160 mL) was added 10% palladium on carbon (0.98 g, 0.92 mmol) and the resulting mixture was stirred vigorously under an atmosphere of hydrogen (ca. 1 atm) for 18 h. The reaction mixture was filtered through a pad of Celite®, washing with EtOH, and the filtrate was concentrated in vacuo to give a crude solid. The crude product was purified by silica gel chromatography, eluting with a gradient of CH2Cl2:EtOAc—100:0 to 60:40, to give the racemic product. Separation of the enantiomers was achieved by HPLC on a ChiralPak® AD colunm, eluting with EtOH:hexanes:Et2NH—60:40:0.04, to give tert-butyl[(3R,5R)-5-(2,3-difluorophenyl)-2-oxo-1-(2,2,2-trifluoroethyl)piperidin-3-yl]carbamate as the first major peak, and tert-butyl[(3S,5S)-5-(2,3-difluorophenyl)-2-oxo-1-(2,2,2-trifluoroethyl)piperidin-3-yl]carbamate, the title compound, as the second major peak. MS: m/z=431.0 (M+Na).

Provenance & Evidence