反应详情

To a solution of D-valine benzyl ester free base (12.92 g, 62 mmol) in dry methylene chloride (120 mL) was added 3,4-(methylenedioxy)phenyl methanol (9.45 g, 62 mmol) and sodium triacetoxyborohydride (18.50 g, 86.8 mmol). After 15 h, the reaction mixture was quenched with saturated aqueous sodium bicarbonate (120 mL) and the aqueous layer was separated and extracted with methylene chloride. The combined methylene chloride layers were washed with brine, dried over magnesium sulfate, and concentrated. The residue was chromatographed (300 g SiO2, 5% ethyl acetate-hexanes) to afford 2(R)-(3,4-methylenedioxy-benzylamino)-3-methylbutyric acid benzyl ester (18 g) as a colorless oil.

1. customthe reaction mixture was quenched with saturated aqueous sodium bicarbonate (120 mL)
2. customthe aqueous layer was separated
3. extractionextracted with methylene chloride
4. washThe combined methylene chloride layers were washed with brine
5. dry with materialdried over magnesium sulfate
6. concentrationconcentrated
7. customThe residue was chromatographed (300 g SiO2, 5% ethyl acetate-hexanes)