methyl (2S,4E)-2-(benzyloxycarbonylamino)-6-oxohex-4-enoate

methyl (2S,4E)-2-(benzyloxycarbonylamino)-6-hydroxyhex-4-enoate

methyl (2S,4E)-2-(benzyloxycarbonylamino)-6-bromohex-4-enoate

(E)-(2S,7S)-2-Amino-7-benzyloxycarbonylamino-oct-4-enedioic acid dimethyl ester

(2S,5R,2'E,5'S)-2-[5'-(benzyloxycarbonylamino)-5'-carbomethoxy-pent-2-ene]-2,5-dihydro-5-isopropyl-3,6-dimethyloxypyrazine