反应详情

To a suspension of stannous trifluoromethanesulfonate (2.18 g) and N-ethylpiperidine (590 mg) in dichloromethane (15 ml) was added dropwise a solution of 2-methyl-2-(trimethylsilyloxy)-3-pentanone (785 mg) in dichloromethane (2 ml) at -78° C. under argon atmosphere. After stirring for 30 minutes, a solution of (3R,4R)-4-acetoxy-3-[(1R)-1-(t-butyldimethylsilyloxy)ethyl]-2-azetidinone (300 mg) in dichloromethane (3 ml) was added dropwise to the mixture. The reaction mixture was allowed to warm to room temperature and stirred at the same temperature for 3 hours. The mixture was quenched with phosphate butter (pH 7). The organic layer was filtered with celite, washed with dichloromethane, dried over magnesium sulfate and evaporated. The residue was chromatographed on silica gel (9 g) eluting with a mixture of ethyl acetate and hexane (1:10, V/V) to give (3S,4R)-3-[(1R)-1-(t-butyldimethylsilyloxy)ethyl]-4-[(1R)-1,3-dimethyl-3-(trimethylsilyloxy)-2-oxobutyl]-2-azetidinone (159 mg).

1. stirringstirred at the same temperature for 3 hours
2. customThe mixture was quenched with phosphate butter (pH 7)
3. filtrationThe organic layer was filtered with celite
4. washwashed with dichloromethane
5. dry with materialdried over magnesium sulfate
6. customevaporated
7. customThe residue was chromatographed on silica gel (9 g)
8. washeluting with a mixture of ethyl acetate and hexane (1:10, V/V)