To a cooled (0° C.) solution of tert-butyl 3-{(1R,2R)-3-[(4R)-4-benzyl-2-oxo-1,3-oxazolidin-3-yl]-2-hydroxy-3-oxo-1-pyridin-2-ylpropyl}benzoate from the previous step (0.068 g, 0.135 mmol) in THF (2 mL), was added 35% hydrogen peroxide (0.061 mL, 0.541 mmol) dropwise, then 1.0M LiOH (0.271 mL, 0.271 mmol) in H2O (0.4 mL). The reaction was stirred for 1.5 hours, at which time HPLC indicated incomplete reaction so additional 35% hydrogen peroxide (0.030 mL, 0.271 mmol) and 1.0M LiOH (0.135 mL, 0.135 mmol) in H2O (0.2 mL) were added and stirring continued for 1 hour. HPLC analysis showed complete consumption of starting material. The mixture was quenched with 10% aqueous Na2SO3 (1 mL) and saturated aqueous NaHCO3 (1 mL), diluted with H2O (20 mL), and washed with 2×20 mL CH2Cl2. The aqueous layer was acidified with 10% aqueous citric acid, extracted with 2×30 mL CH2Cl2, dried over MgSO4, filtered, and the solvent removed under reduced pressure to give (2R,3R)-3-[3-(tert-butoxycarbonyl)phenyl]-2-hydroxy-3-pyridin-2-ylpropanoic acid as a yellow oil (0.020 g, 43%). TPLC RT=1.44 min, method B; M+H=344.
