Acetic Acid → allyl (5R,6S)-3-[(E)-2-{(2S)-1-allyloxycarbonylpyrrolidin-2-yl}-1-methylethenyl]-6-[(1R)-1-hydroxyethyl]-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate

Participants

Reaction Steps

To a solution of 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) in tetrahydrofuran (60 ml) were added acetic acid (5.6 ml) and a 1M solution of tetrabutylammonium fluoride in tetrahydrofuran (49 ml) at 0° C. After standing at ambient temperature for 7 hours and at 5° C. for 14 hours, the reaction mixture was taken up into a mixture of ethyl acetate (200 ml) and water (200 ml). After adjusting pH to around 7 with aqueous sodium hydrogen carbonate, the organic layer was separated, washed in turn with water and brine, and dried over magnesium sulfate. Removal of the solvent gave a residue, which was chromatographed on silica gel (150 ml) eluting with a mixture of n-hexane and ethyl acetate (8:2-3:7 V/V) to give allyl (5R,6S)-3-[(E)-2-{(2S)-1-allyloxycarbonylpyrrolidin-2-yl}-1-methylethenyl]-6-[(1R)-1-hydroxyethyl]-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate (2.82 g).

Provenance & Evidence