(S)-2-((S)-2-{[(1R,2R)-2-((4S,5S)-3-tert-Butoxycarbonyl-4-isobutyl-2,2-dimethyl-oxazolidin-5-yl)-cyclopentanecarbonyl]-amino}-propionylamino)-pentanedioic acid dibenzyl ester

(4S,5S)-5-((1R,2R)-2-{(S)-1-[(S)-3-Benzyloxycarbonyl-1-((S)-1-benzyloxycarbonyl-2-phenyl-ethylcarbamoyl)-propylcarbamoyl]-ethylcarbamoyl}-cyclopentyl)-4-isobutyl-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

(4S)-isobutyl-(5S)-(1-methoxycarbonylmethyl-allyl)-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester

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