allyl (8S,9R,10S)-5-(carbamoyl)methyl-10-[(R)-1-hydroxyethyl]-11-oxo-1,5-diazatricyclo[7.2.0.03,8]undec-2-ene-2-carboxylate

(3S,4R)-4-[4-(allyloxycarbonyl)-1-benzyl-3-oxopiperidin-4-yl]-3-[(R)-1-(tert-butyldimethylsilyloxy)ethyl]-2-azetidinone

allyl (8S,9R,10S)-5-methyl-10-[(R)-1-hydroxyethyl]-11-oxo-1,5-diazatricyclo[7.2.0.03,8]undec-2-ene-2-carboxylate

allyl (8S,9R,10S)-5-acetyl-10-[(R)-1-hydroxyethyl]-11-oxo-1,5-diazatricyclo[7.2.0.03,8]undec-2-ene-2-carboxylate

allyl (8S,9R,10S)-5-carbamoyl-10-[(R)-1-hydroxyethyl]-11-oxo-1,5-diazatricyclo[7.2.0.03,8]undec-2-ene-2-carboxylate