反应详情

温度

-78 °C

31 ml of 1.69M n-butyllithium in hexane was dissolved in 30 ml of tetrahydrofuran, and 7.1 ml of diisopropylamine was added under cooling with ice. The resulting solution was stirred at the same temperature for 30 minutes at 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 a solution of 5.58 g of tert-butyl bromoacetate and 4.66 g of hexamethylphosphoric triamide in 20 ml of tetrahydrofuran was added dropwise at -50° C. or below. Then, 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 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 3.8 g of the title compound as a yellow oily substance.

1. temperatureunder cooling with ice
2. stirringthe reaction solution was stirred at -20° C. for 1.5 hours
3. temperatureThe reaction solution was cooled to -78° C.
4. stirringThen, the reaction solution was stirred at room temperature for 1 hour
5. extractionextracted with diethyl ether
6. washthe organic layer was washed with saturated aqueous sodium hydrogencarbonate and saturated aqueous sodium chloride
7. dry with materialdried over anhydrous magnesium sulfate
8. filtrationThe desiccant was filtered off
9. distillationthe solvent was distilled off under reduced pressure
10. customThe residue was purified by silica gel column chromatography [hexane/ethyl acetate=5/1→4/1]