184429-84-3

195197-94-5

184429-84-3

Oxalyl chloride (13.6 mL, 0.16 mol) was dissolved in anhydrous dichloromethane (150 mL) under nitrogen protection and cooled to -78 °C. Dimethyl sulfoxide (15.2 mL, 0.21 mol) was slowly added dropwise over 30 min, and after completion of the dropwise addition, stirring was continued for 1 h at -78 °C. Subsequently, a solution of tert-butyl 3-((tert-butyldimethylsilyl)oxy)-2-hydroxypropylcarbamate (32.6 g, 0.11 mol) in dichloromethane (50 mL) was added dropwise over 20 minutes. After the reaction mixture continued to be stirred at -78 °C for 1 h, triethylamine (59.6 mL, 0.43 mol) was added. The cooling bath was removed and the reaction mixture was allowed to slowly warm to room temperature. The reaction mixture was transferred to a partitioning funnel, water (100 mL) and dichloromethane (70 mL) were added for partitioning, and the aqueous layer was further extracted with dichloromethane (2 x 70 mL). The organic layers were combined, dried with anhydrous sodium sulfate and concentrated under nitrogen protection. The crude product was purified by silica gel column chromatography using 5% ethyl acetate in hexane solution as eluent to afford tert-butyl 3-((tert-butyldimethylsilyl)oxy)-2-oxopropylcarbamate (29.8 g, 92%) as a light yellow oil.1H-NMR (300 MHz, CDCl3) δ: 0.11 (6H, s), 0.94 (9H, s), and 1.47 (9H, s), 3.92 (2H, s), 4.26 (2H, d, J=4.6 Hz), 5.22 (1H, br s).