反应详情

A mixture of triethyl phosphite (1.43 g), toluene (3 ml) and a mixture (1.0 g) of (3S,4S)-1-(allyloxyoxalyl)-3-[(1R)-1-(tert-butyldimethylsilyloxy)ethyl]-4-[(1R)-1-{(methylthio)thiocarbonyl}ethyl]-2-oxoazetidine and (3S,4S)-1-(allyloxyoxalyl)-3-[(1R)-1-(tert-butyldimethylsilyloxy)ethyl]-4-[(1S)-1-{(methylthio)thiocarbonyl}ethyl]-2-oxoazetidine was heated at 80° C. for 26 hours and then refluxed for 16 hours. After removal of the solvent, the residue was dissolved in hexane, washed with water, dried, and concentrated in vacuo. The oily residue was purified by silica gel column chromatography [diethyl ether-hexane (1:3, V/V)] to afford a mixture (118 mg) of allyl (4R,5S,6S)-6-[(1R)-1-(tert-butyldimethylsilyloxy)ethyl]-4-methyl-3-methylthio-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate and allyl (4S,5S,6S)-6-[(1R)-1-(tert-butyldimethylsilyloxy)ethyl]-4-methyl-3 -methylthio-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate.

1. temperaturerefluxed for 16 hours
2. customAfter removal of the solvent
3. dissolutionthe residue was dissolved in hexane
4. washwashed with water
5. customdried
6. concentrationconcentrated in vacuo
7. customThe oily residue was purified by silica gel column chromatography [diethyl ether-hexane (1:3, V/V)]