反应详情

To a solution of 1.1 equivalents of freshly prepared lithium diisopropylamide in 3 ml anhydrous tetrahydrofuran under a nitrogen atmosphere at -78° is added a solution of 1-(t-butyldimethylsilyl)-4-(2'-acetoxyethyl)-2-azetidinone (61 mg, 0.225 mmole) in 1 ml anhydrous tetrahydrofuran which has been cooled to -78°. After 12 minutes the reaction mixture is poured into 5 ml water. The solution is saturated with sodium chloride and extracted with methylene chloride. The combined methylene chloride solutions are washed with brine, dried over magnesium sulfate and filtered. Evaporation of the filtrate under reduced pressure gives 50 mg of crude product. Purification by preparative thick-layer chromatography on silica gel developing with ethyl acetate gives 1-(t-butyldimethylsilyl)-3-acetyl-4-(2'-hydroxyethyl)-2-azetidinone (19 mg).

1. temperaturehas been cooled to -78°
2. extractionextracted with methylene chloride
3. washThe combined methylene chloride solutions are washed with brine
4. dry with materialdried over magnesium sulfate
5. filtrationfiltered
6. customEvaporation of the filtrate under reduced pressure
7. customgives 50 mg of crude product
8. customPurification by preparative thick-layer chromatography on silica gel developing with ethyl acetate