Allyl 2-[(3S,4R)-4-[(E)-4-{(2S)-1-allyloxycarbonylpyrrolidin-2-yl}-3-methyl-2-oxo-3-butenyl]-3-{(1R)-1-t-butyldimethylsilyloxyethyl}-2-oxoazetidin-1-yl]-2-triphenylphosphoranylideneacetate → allyl (5R,6S)-3-[(E)-2-{(2S)-1-allyloxycarbonylpyrrolidin-2-yl}-1-methylethenyl]-6-[(1R)-1-t-butyldimethylsilyloxyethyl]-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

Allyl 2-[(3S,4R)-4-[(E)-4-{(2S)-1-allyloxycarbonylpyrrolidin-2-yl}-3-methyl-2-oxo-3-butenyl]-3-{(1R)-1-t-butyldimethylsilyloxyethyl}-2-oxoazetidin-1-yl]-2-triphenylphosphoranylideneacetate (9.78 g) was dissolved in degassed xylene (150 ml) and the solution was heated to 150° C. for 10 hours. Evaporation of the mixture gave a residue, which was chromatographed on silica gel (250 ml) eluting with a mixture of n-hexane and ethyl acetate (2:8-7:3 V/V) to give allyl (5R,6S)-3-[(E)-2-{(2S)-1-allyloxycarbonylpyrrolidin-2-yl}-1-methylethenyl]-6-{(1R)-1-t-butyldimethylsilyloxyethyl]-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate (5.36 g).

Provenance & Evidence