反应详情

温度

0 °C

tert-Butyl [(1S)-1-methyl-2-oxoethyl]carbamate (7.21 g) and ethyl bromodifluoroacetate (25.1 g) were dissolved in THF (65 mL), and the solution was added dropwise to a suspension of zinc powder (25.1 g) in THF (14 mL) at room temperature over 30 min. The suspension was heated under reflux for 30 min and cooled to 0° C. A 1 mol/L aqueous hydrochloric acid solution (200 mL) was added, and the mixture was extracted with ethyl acetate (100 mL). The extracted organic layer was washed with water (100 mL) and saturated brine (100 mL), dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: ethyl acetate/hexane=1/10→3/10) to give the title compound as a pale-yellow oil (yield: 5.45 g, 44%).

1. temperatureThe suspension was heated
2. temperatureunder reflux for 30 min
3. extractionthe mixture was extracted with ethyl acetate (100 mL)
4. washThe extracted organic layer was washed with water (100 mL) and saturated brine (100 mL)
5. dry with materialdried over anhydrous magnesium sulfate
6. concentrationconcentrated under reduced pressure
7. customThe residue was purified by silica gel column chromatography (eluent: ethyl acetate/hexane=1/10→3/10)