反应详情

To a solution of N-Boc-valine (10 g, 46.08 mmol) in EtOH (70 mL) was added Cs2CO3 (14.97 g, 46.06 mmol) in a solution of H2O (30 mL). The mixture was stirred at RT for 30 mins, co-evaporated with toluene to dryness, re-dissolved in DMF (100 mL) and cooled in an ice bath. Chloroiodomethane (81.1 g, 460.8 mmol) was added dropwise at 0° C. The mixture was stirred at RT in the dark (tin foil) for 12 h. The mixture was treated with H2O (200 mL), extracted with EtOAc (3×100 mL). The combined organic layers were dried over Na2SO4, filtered and concentrated. The crude product was purified by column chromatography on silica gel eluted with PE:EA=100:1 to 60:1 to give (S)-chloromethyl 2-((tert-butoxycarbonyl)amino)-3-methylbutanoate (37%).

1. temperaturecooled in an ice bath
2. extractionextracted with EtOAc (3×100 mL)
3. dry with materialThe combined organic layers were dried over Na2SO4
4. filtrationfiltered
5. concentrationconcentrated
6. customThe crude product was purified by column chromatography on silica gel
7. washeluted with PE