(1S,5R,7R)-4-((E)-But-2-enoyl)-10,10-dimethyl-3-phenyl-3,4-diaza-tricyclo[5.2.1.01,5]decan-2-one

benzyl but-2-enoyl(tert-butyldiphenylsilyloxy)carbamate

(E)-1-((3S,3aS,6aS)-2-Benzyl-4,4-dioxo-3-phenyl-hexahydro-1-oxa-4λ6-thia-2,5-diaza-pentalen-5-yl)-but-2-en-1-one

but-2-enoic acid 1-[methoxy(diphenyl)methyl]-7,7-dimethyl-bicyclo[2.2.1]hept-2-yl ester

(E)-But-2-enoic acid (S)-3-[((E)-but-2-enoyl)-((S)-1-phenyl-ethyl)-amino]-2-methyl-propyl ester