反应详情

温度

5 °C

To a mixture of dimethylformamide (4.2 ml) and tetrahydrofuran (10 ml) was added phosphorus oxychloride (4.2 ml) at 5° C. After stirring at 5° C. for 30 minutes, to the mixture were added successively tetrahydrofuran (60 ml) and N-allyloxycarbonyl-N-methylglycine (8.7 g). The mixture was stirred for 30 minutes at 5° C. (solution A). To a solution of (2S)-1-allyloxycarbonyl-2-(2-methyl-3-oxo-1-butenyl)pyrrolidine (10.0 g) in tetrahydrofuran (160 ml) were added successively triphenylphosphine (5.5 g), 5,5-dimethyl-1,3-cyclohexanedione (dimedone) (5.8 g), acetic acid (4.8 ml) and tetrakis(triphenylphosphine)palladium(0) (2.4 g). After stirring at ambient temperature for 30 minutes, the mixture was taken up into a mixture of ethyl acetate (100 ml) and water (100 ml). After adjusting to around pH 2 with 1N hydrochloric acid, the aqueous layer was separated, washed with ethyl acetate and tetrahydrofuran (200 ml) was added thereto. After adjusting to around pH 8.5 with 20% aqueous sodium hydroxide, to the mixture was added dropwise the solution A. After stirring at 5° C. for 1 hour, the mixture was extracted with ethyl acetate. The organic layer was washed with water and dried over magnesium sulfate. Removal of the solvent gave a residue, which was chromatographed on silica gel (300 ml) eluting with a mixture of n-hexane and ethyl acetate (5.5-3.7 V/V) to give (2S)-1-(N-allyloxycarbonyl-N-methylaminoacetyl)-2-(2-methyl-3-oxo-1-butenyl)pyrrolidine (3.4 g).

1. stirringAfter stirring at ambient temperature for 30 minutes
2. customthe aqueous layer was separated
3. washwashed with ethyl acetate and tetrahydrofuran (200 ml)
4. additionwas added
5. additionwas added dropwise the solution A
6. stirringAfter stirring at 5° C. for 1 hour
7. extractionthe mixture was extracted with ethyl acetate
8. washThe organic layer was washed with water
9. dry with materialdried over magnesium sulfate
10. customRemoval of the solvent
11. customgave a residue, which
12. customwas chromatographed on silica gel (300 ml)
13. washeluting with a mixture of n-hexane and ethyl acetate (5.5-3.7 V/V)