(4S,5S)-5-[(1R,2R)-2-((S)-1-Benzyloxycarbonyl-ethylcarbamoyl)-cyclopentyl]-4-isobutyl-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester

(4S,5S)-4-Isobutyl-2,2-dimethyl-5-{(1R,2R)-2-[(S)-1-(2,2,2-trichloro-ethoxycarbonyl)-ethylcarbamoyl]-cyclopentyl}-oxazolidine-3-carboxylic acid tert-butyl ester

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

(S)-2-[((1R,2R)-2-{(1S,2S)-2-[(S)-2-((S)-2-Acetylamino-4-methyl-pentanoylamino)-4-methylsulfanyl-butyrylamino]-1-hydroxy-4-methyl-pentyl}-cyclopentanecarbonyl)-amino]-3-methyl-butyric acid

(5S)-((2R)-butylcarbamoyl-cyclopentyl)-(4S)-isobutyl-2,2-dimethyloxazolidine-3-carboxylic acid tert-butyl ester