To a solution of (R)-4-benzyl-3-((2R,3R,4S)-3-hydroxy-2-phenethyl-4-((triisopropylsilyl)oxy)pentanoyl)-oxazolidin-2-one (2.52 g, 4.55 mmol) in EtOH (18 mL) was added 1 N HCl (2 mL, 2 mmol) and the mixture heated to 80° C. for a 3 h. The solution was concentrated in vacuo, and the residue was dissolved in CH2Cl2, loaded onto a pre-packed Celite® cartridge, and purified by flash chromatography (SiO2, 0→100% EtOAc/hexanes) gave (3R,4R,5S)-4-hydroxy-5-methyl-3-phenethyldihydrofuran-2(3H)-one (840 mg, 3.81 mmol, 84% yield) and (R)-4-benzyloxazolidin-2-one (710 mg, 4.01 mmol, 88% yield). The title product was obtained as a colorless, amorphous solid: 1H NMR (600 MHz, CDCl3) δ 7.33-7.28 (m, 2H), 7.25-7.19 (m, 3H), 4.20-4.13 (m, 1H), 3.80 (dd, J=8.9, 7.3 Hz, 1H), 2.96-2.88 (m, 1H), 2.86-2.79 (m, 1H), 2.59-2.52 (m, 1H), 2.28-2.17 (m, 2H), 1.97-1.88 (m, 1H), 1.43 (d, J=6.3 Hz, 3H); 13C NMR (151 MHz, CDCl3) δ 175.91, 140.94, 128.64, 128.51, 126.34, 79.89, 79.36, 47.98, 32.81, 30.25, 18.19; ESIMS m/z 221 ([M+H]+).
