反应详情

温度

-78 °C

31 ml of 1.69M hexane solution of n-butyllithium 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 and then cooled to -78° C. 4.94 g of diethyl (S)-malate in 20 ml of tetrahydrofuran was added dropwise at or below -50° C., and the resulting 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 or below -50° C. The resulting 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, the solvent was evaporated in vacuo. 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
2. customthe resulting reaction solution
3. stirringwas stirred at -20° C. for 1.5 hours
4. temperatureThe reaction solution was cooled to -78° C.
5. customThe resulting reaction solution
6. stirringwas stirred at room temperature for 1 hour
7. extractionextracted with diethyl ether
8. washthe organic layer was washed with saturated aqueous sodium hydrogencarbonate and saturated aqueous sodium chloride
9. dry with materialdried over anhydrous magnesium sulfate
10. filtrationThe desiccant was filtered off
11. customthe solvent was evaporated in vacuo
12. customThe residue was purified by silica gel column chromatography [hexane/ethyl acetate=5/1→4/1]