反应详情

温度

-78 °C

To a suspension of stannous trifluoromethanesulfonate (8.35 g) and N-ethylpiperidine (3.79 ml) in dichloromethane (60 ml) was added dropwise a solution of 3-propionyl-2-thioxothiazolidine (4.12 g) in dichloromethane (35 ml) at -78° C. under nitrogen atmosphere. After stirring at -78° C. for 30 minutes, a solution of (3R,4R)-4-acetoxy-3-[(1R)-1-(t-butyldimethylsilyloxy)ethyl]-2-azetidinone (2.25 g) in dichloromethane (8 ml) was added to the reaction mixture, and the reaction mixture was stirred at 0° C. for 30 minutes and then at room temperature for 20 minutes. The reaction mixture was poured into aqueous sodium bicarbonate solution (100 ml) and the precipitated white mass was removed by passing through a layer of celite. The organic layer was separated and washed with 10% aqueous sodium chloride solution (100 ml×2). The organic solution was dried over magnesium sulfate and evaporated. The residue was chromatographed on silica gel (185 g) eluting with a mixture of acetone and dichloromethane (2:98, V/V) to give (3S,4R)-3-[(1R)-1-(t-butyldimethylsilyloxy)ethyl]-4-[(1RS)-1-methyl-2-oxo-2-(2-thioxothiazolidin-3-yl)ethyl]-2-azetidinone (2.39 g).

1. stirringthe reaction mixture was stirred at 0° C. for 30 minutes
2. waitat room temperature for 20 minutes
3. customthe precipitated white mass was removed
4. customThe organic layer was separated
5. washwashed with 10% aqueous sodium chloride solution (100 ml×2)
6. dry with materialThe organic solution was dried over magnesium sulfate
7. customevaporated
8. customThe residue was chromatographed on silica gel (185 g)
9. washeluting with a mixture of acetone and dichloromethane (2:98, V/V)