To a solution of (4S,5S)-4-hydroxymethyl-5-phenyl-oxazolidin-2-one (3.50 g, 17.2 mmol), NEt3 (4.80 mL, 34.4 mmol), and DMAP (105 mg, 861 μmol) in DMF (20 mL) was added dropwise TBDPSCl (4.86 mL, 18.9 mmol) at room temperature. The reaction was stirred for 3 hours at room temperature. The reaction mixture was then concentrated and diluted with TBME, the organic layers were separated, washed with aqueous NaHCO3 and brine, dried over MgSO4, and concentrated. The residue was purified by column chromatography (120 g SiO2) using EtOAc in heptane from 0% to 60% in order to give the title compound as a white solid (4.28 g, 57%). LC-MS: [M+H] 432.2; Rt 1.36 min; (LCMS method 2).
