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

(2R,4S,5S)-2-Benzyl-5-tert-butoxycarbonylamino-4-(tert-butyl-dimethyl-silanyloxy)-6-methyl-heptanoic acid

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