(S)-methyl 3-(tert-butoxycarbonylamino)-4-(trifluoromethanesulfonate)-4-(2,4,5-trifluorophenyl)-n-butyrate
3-(R)-tert-butoxycarbonylamino-4-(2,4,5-trifluorophenyl)butyric acid methyl ester
(3R)-3-[(1,1-dimethylethoxycarbonyl)amino]-4-(2,4,5-trifluorophenyl)butanoic acid
methyl (3 S)-3-(tert-butoxycarbonylamino)-4-hydroxy-4-(2,4,5-trifluorophenyl)butyrate