allyl 1-benzyl-3-oxo-4-piperidinecarboxylate

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

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

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