反应详情

温度

-78 °C

A suspension (300 mL) of cerium chloride (47 g) in THF was cooled to −78° C., and 3 mol/L methylmagnesium bromide-diethyl ether solution (56 mL) was added dropwise while adjusting the temperature of the solution to not higher than −70° C. After the completion of the dropwise addition, the mixture was stirred at −78° C. for 30 min, and a solution (60 mL) of benzyl (2S)-2-methyl-3-oxopyrrolidine-1-carboxylate (18 g) in THF was added dropwise while adjusting the temperature of the solution to not higher than −70° C. The reaction mixture was warmed to 0° C. over 2 hr, ethyl acetate (1 L) was added, and the insoluble material was filtered off. Water was added to the filtrate and then the mixture was partitioned. The organic layer was washed with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate=9/1→1/1) to give the title compound as a colorless oil (yield: 16.2 g, yield: 84%).

1. customhigher than −70° C
2. additionAfter the completion of the dropwise addition
3. customhigher than −70° C
4. temperatureThe reaction mixture was warmed to 0° C. over 2 hr
5. filtrationthe insoluble material was filtered off
6. additionWater was added to the filtrate
7. customthe mixture was partitioned
8. washThe organic layer was washed with saturated brine
9. dry with materialdried over anhydrous sodium sulfate
10. concentrationconcentrated under reduced pressure
11. customThe residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate=9/1→1/1)