To a solution of (4S,5S)-4-(hydroxymethyl)-5-(4-methoxyphenyl)oxazolidin-2-one [545435-91-4] (0.68 g, 3.05 mmol) and imidazole (0.249 g, 3.66 mmol) in DMF (10 mL) was added dropwise TBDPSCl (0.97 mL, 3.66 mmol) at 0-5° C. The reaction mixture was allowed to warm to RT and was stirred overnight at RT. The reaction mixture was concentrated and the residual oil was dissolved in TBME and washed with 10% aqueous KHSO4, H2O, saturated NaHCO3 solution and brine, dried over MgSO4, filtered and concentrated. The residue was purified by column chromatography using EtOAc in heptane from 5% to 50% in order to give the title compound as a white foam (1.62 g, 55%). TLC (heptane/EtOAc 1:1) Rf=0.44; LC-MS: [M+H] 462; Rt 1.36 min; (LCMS method 2). 1H NMR (400 MHz, CDCl3): 7.65 (d, 4H), 7.35-7.60 (m, 6H), 7.24 (d, 2H), 6.92 (d, 2H), 5.24 (d, 1H), 5.20 (br s, 1H), 3.84 (m, 4H), 3.77 (m, 2H), 1.09 (s, 9H).
