反应详情

Allyl bromide (2.48 mL, 29.3 mmol) was added to a solution of (1R*,5S*)-7-benzyl-3-oxa-7-azabicyclo[3.3.0]octan-2-one (4.25 g, 19.6 mmol) in tetrahydrofuran (98 mL) with stirring under salt-ice cooling. A 1 M solution of lithium hexamethyldisilazide in tetrahydrofuran (23.5 mL, 23.5 mmol) was added dropwise under cooling with ice-acetone. The mixture was stirred for two hours while gradually heating to room temperature. A saturated ammonium chloride solution (200 mL) was added to the reaction solution, followed by extraction with ethyl acetate (100 mL×2). The organic layer was washed with water (250 mL) and brine (250 mL) and dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (hexane:ethyl acetate=100:0→95:5→90:10→84:16→80:20→75:25→66:34→50:50) to give 1.51 g of the title compound.

1. stirringThe mixture was stirred for two hours
2. extractionfollowed by extraction with ethyl acetate (100 mL×2)
3. washThe organic layer was washed with water (250 mL) and brine (250 mL)
4. dry with materialdried over anhydrous sodium sulfate
5. filtrationAfter filtration
6. concentrationthe filtrate was concentrated under reduced pressure
7. customThe resulting residue was purified by silica gel column chromatography (hexane:ethyl acetate=100:0→95:5→90:10→84:16→80:20→75:25→66:34→50:50)