反应详情

2-Amino-3,3-dimethyl-butyric acid (551 mg, 4.2 mmol) was dissolved in CH3CN (15 mL), H2O (3 mL) and MeOH (3 mL). Carbonic acid 4-nitro-phenyl ester tetrahydro-furan-3-yl ester (1.6 g, 6.3 mmol) and DIEA (1.46 mL, 8.4 mmol) were added. This reaction mixture was allowed to stir at room temperature for 16 h. After concentrated, diluted with EtOAc, washed with brine and H2O, dried over Na2SO4, the crude product was purified on silica (12 g, 25-75% EtOAc/hexanes) to give intermediate 3,3-dimethyl-2-(tetrahydro-furan-3-yloxycarbonylamino)-butyric acid as a white solid (670 mg, 65%).

1. concentrationAfter concentrated
2. additiondiluted with EtOAc
3. washwashed with brine and H2O
4. dry with materialdried over Na2SO4
5. customthe crude product was purified on silica (12 g, 25-75% EtOAc/hexanes)