反应详情

温度

-78 °C

31 ml of 1.69M n-butyllithium in hexane was dissolved in 30 ml of tetrahydrofuran, stirred with 7.1 ml of diisopropylamine under cooling with ice for 30 minutes and then cooled to -78° C. 4.94 g of diethyl (S)-malate in 20 ml of tetrahydrofuran was added dropwise at -50° C. or below, and the reaction solution was stirred at -20° C. for 1.5 hours. The reaction solution was cooled to -78° C., and 5.58 g of tert-butyl bromoacetate and 4.66 g of hexamethylphosphoryl triamide in 20 ml of tetrahydrofuran were added dropwise at -50° C. or below. The reaction solution was stirred at room temperature for 1 hour. The reaction solution was poured into 150 ml of 0.5N hydrochloric acid and extracted with diethyl ether, and the organic layer was washed with saturated aqueous sodium hydrogencarbonate and saturated aqueous sodium chloride and then dried over anhydrous magnesium sulfate. The desiccant was filtered off, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography [hexane/ethyl acetate=5/1→4/1] to give 3.88 g of the title compound as a yellow oily substance.

1. temperatureunder cooling with ice for 30 minutes
2. temperatureThe reaction solution was cooled to -78° C.
3. stirringThe reaction solution was stirred at room temperature for 1 hour
4. extractionextracted with diethyl ether
5. washthe organic layer was washed with saturated aqueous sodium hydrogencarbonate and saturated aqueous sodium chloride
6. dry with materialdried over anhydrous magnesium sulfate
7. filtrationThe desiccant was filtered off
8. distillationthe solvent was distilled off under reduced pressure
9. customThe residue was purified by silica gel column chromatography [hexane/ethyl acetate=5/1→4/1]