反应详情

To a 0° C. solution of (4S,5R)-5-[3,5-bis(trifluoromethyl)phenyl]-3-[2-(hydroxymethyl)-5-(trifluoromethyl)benzyl]-4-methyl-1,3-oxazolidin-2-one (210 mg, 0.419 mmol) in CH2Cl2 (4 mL) was added CBr4 (292 mg, 0.880 mmol) and a solution of PPh3 (220 mg, 0.838 mmol) in CH2Cl2 (4 mL). The mixture was allowed to warm to room temperature, and, after 90 minutes had elapsed, it was concentrated on to silica gel. Purification of the residue by flash chromatography on silica gel (10 to 50% EtOAc/hexanes) afforded (4S,5R)-5-[3,5-bis(trifluoromethyl)phenyl]-3-[2-(bromomethyl)-5-(trifluoromethyl)benzyl]-4-methyl-1,3-oxazolidin-2-one. Rf=0.10 (50% EtOAc/hexanes). LCMS=564.0 (M+1)+. 1H NMR (CDCl3, 500 MHz) δ 7.88 (s, 1H), 7.78 (s, 2H), 7.63-7.57 (m, 2H), 7.52 (s, 1H), 5.79 (d, J=8.0 Hz, 1H), 5.09 (d, J=15.8 Hz, 1H), 4.61 (dd, J=13.8, 10.5 Hz, 2H), 4.27 (d, J=15.8 Hz, 1H), 4.06-1.00 (m, 1H), 0.82 (d, J=6.4 Hz, 3H).

1. concentrationit was concentrated on to silica gel
2. customPurification of the residue by flash chromatography on silica gel (10 to 50% EtOAc/hexanes)