(3S,4S)-1-[1-(allyloxycarbonyl)-1-(triphenylphosphoranediyl)methyl]-3-[(1R)-1-(tert-butyldimethylsilyloxy)ethyl]-4-[(1R)-1-{(methylthio)thiocarbonyl}ethyl]-2-oxoazetidine → 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

Participants

Reaction Steps

A solution of (3S,4S)-1-[1-(allyloxycarbonyl)-1-(triphenylphosphoranediyl)methyl]-3-[(1R)-1-(tert-butyldimethylsilyloxy)ethyl]-4-[(1R)-1-{(methylthio)thiocarbonyl}ethyl]-2-oxoazetidine (325 mg) in toluene (3 ml) was heated under reflux for 4.5 hours. The solvent was removed under reduced pressure and the residue was purified by silica gel column chromatography [ethyl acetate-hexane (1:3, V/V)] to afford 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 (164 mg).

Provenance & Evidence