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

allyl (8S,9R,10S)-5-[3-[[N,N'-bis(allyloxycarbonyl)amidino]amino]propionyl]-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

allyl (8S,9R,10S)-5-[N-(allyloxycarbonyl)acetimidoyl]-10-[(R)-1-(tert-butyldimethylsilyloxy)ethyl]-11-oxo-1,5-diazatricyclo[7.2.0.03,8]undec-2-ene-2-carboxylate

allyl (8S,9R,10S)-5-[3-(tert-butoxycarbonylamino)propionyl]-10-[(R)-1-(tert-butyldimethylsilyloxy)ethyl]-11-oxo-1,5-diazatricyclo[7.2.0.03,8]undec-2-ene-2-carboxylate