Into a solution of benzyl 2,4-bis(benzyloxy)-5-iodonicotinate (1.0 g, 1.8 mmol) in THF (8.0 mL) at −45° C. was added a solution of i-PrMgCl—LiCl (1.3 M×2.8 mL, 3.6 mmol) dropwise. The mixture was stirred at −45° C. for 30 min, into which triisopropyl borate (0.87 mL, 3.78 mmol) was added dropwise. After stirring at −45° C. for 15 min, the temperature was allowed to rise to room temperature slowly. The mixture was stirred at room temperature for 1.5 h then cooled to −20° C., into which peracetic acid (32%, 0.79 mL, 3.78 mmol) was added. The mixture was stirred at room temperature for another 30 min before it was treated with water (50 mL). The mixture was extracted with ethyl acetate. The organic layers were combined and washed with brine, dried over sodium sulfate, evaporated and purified by silica chromatography (0-30% ethyl acetate in hexanes) to give benzyl 2,4-bis(benzyloxy)-5-hydroxynicotinate (0.29 g, 36%).
