(E)-(S)-4-[(2R,4S,5S)-5-tert-Butoxycarbonylamino-4-(tert-butyl-dimethyl-silanyloxy)-6-methyl-2-(3-methyl-but-2-enyl)-heptanoylamino]-5-((S)-2-oxo-pyrrolidin-3-yl)-pent-2-enoic acid ethyl ester

(2S,4S)-2-(2-Amino-ethyl)-4-tert-butoxycarbonylamino-pentanedioic acid dimethyl ester

4S-amino-5-(2-oxopyrrolidin-3S-yl)pent-2-enoic acid ethyl ester

tert-butyl (S)-1-((S)-tetrahydro-5-oxofuran-2-yl)-2-methylpropylcarbamate

(4S,5S)-5-tert-Butoxycarbonylamino-4-hydroxy-6-methyl-heptanoic acid ethyl ester