{(S)-1-[(S)-2-((1S,2R)-1-Benzyl-3,3-difluoro-2-hydroxy-3-phenethylcarbamoyl-propylcarbamoyl)-pyrrolidine-1-carbonyl]-2-methyl-propyl}-carbamic acid tert-butyl ester

(S)-2-[(1S,2R)-1-Benzyl-3-(3-benzyloxycarbonyl-phenylcarbamoyl)-3,3-difluoro-2-hydroxy-propylcarbamoyl]-pyrrolidine-1-carboxylic acid tert-butyl ester

3-((3R,4S)-4-{[(S)-1-((S)-2-tert-Butoxycarbonylamino-3-methyl-butyryl)-pyrrolidine-2-carbonyl]-amino}-2,2-difluoro-3-hydroxy-5-phenyl-pentanoylamino)-propionic acid benzyl ester

((3R,4S)-4-{[(S)-1-((S)-2-tert-Butoxycarbonylamino-3-methyl-butyryl)-pyrrolidine-2-carbonyl]-amino}-2,2-difluoro-3-hydroxy-5-phenyl-pentanoylamino)-acetic acid benzyl ester

3-((3R,4S)-4-{[(S)-1-((S)-2-tert-Butoxycarbonylamino-3-methyl-butyryl)-pyrrolidine-2-carbonyl]-amino}-2,2-difluoro-3-hydroxy-5-phenyl-pentanoylamino)-benzoic acid benzyl ester