(4S)-isobutyl-(5S)-((2R)-methoxycarbonyl-4-oxo-cyclopentyl)-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester

(5S)-(1-formyl-2-methoxycarbonyl-ethyl)-(4S)-isobutyl-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester

(S)-2-({(1R,2R)-2-[(1S,2S)-2-((S)-2-tert-Butoxycarbonylamino-4-methylsulfanyl-butyrylamino)-1-hydroxy-4-methyl-pentyl]-cyclopentanecarbonyl}-amino)-propionic acid 2,2,2-trichloro-ethyl ester

(5S)-((Z)-2-bromo-2-methoxycarbonyl-vinyl)-(4S)-isobutyl-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester

(S)-2-[((1R,2R)-2-{(1S,2S)-2-[(S)-2-tert-Butoxycarbonylamino-3-(trityl-carbamoyl)-propionylamino]-1-hydroxy-4-methyl-pentyl}-cyclopentanecarbonyl)-amino]-propionic acid benzyl ester