反应详情

温度

90 °C

To a suspension of sodium hydride (8.7 g, 218 mmol, 60% suspension) in dimethylformaamide (250 mL) at 0° C. was added diethyl 2-(tert-butoxycarbonylamino)malonate (50.0 g, 182 mmol) in dimethylformaamide (250 mL). After stirring for 30 minutes, 4-bromobut-1-ene (29.5 g, 218 mmol, 22.2 mL) was added and the mixture was warmed to 90° C. After stirring an additional 4 h, the solution was cooled to room temperature and the solvents were removed by evaporation. The resulting residue was diluted with ethyl acetate (1.0 L), washed successively with water (2×250 mL), saturated aqueous sodium chloride (1×200 mL) and concentrated. Purification using a combiflash system (330 g silica column, eluted with 15-50% ethyl acetate in heptanes) gave diethyl 2-(but-3-enyl)-2-(tert-butoxycarbonylamino)malonate (54 g, 90%). 1H NMR (CDCl3) δ 5.92 (bs, 1H), 5.79-5.71 (m, 1H), 5.03-4.93 (m, 2H), 4.24-4.19 (m, 4H), 2.36 (m, 2H), 1.96-1.93 (m, 2H), 1.42 (s, 9H), 1.27-1.24 (m, 6H).

1. stirringAfter stirring an additional 4 h
2. temperaturethe solution was cooled to room temperature
3. customthe solvents were removed by evaporation
4. additionThe resulting residue was diluted with ethyl acetate (1.0 L)
5. washwashed successively with water (2×250 mL), saturated aqueous sodium chloride (1×200 mL)
6. concentrationconcentrated
7. customPurification
8. washa combiflash system (330 g silica column, eluted with 15-50% ethyl acetate in heptanes)