4-{(S)-1-[(S)-tert-Butoxycarbonylamino-(2-trimethylsilanyl-ethoxycarbonyl)-methyl]-2-methyl-propoxy}-benzoic acid

(2S,3S)-3-[4-(2-Benzyloxycarbonyl-acetyl)-phenoxy]-2-tert-butoxycarbonylamino-4-methyl-pentanoic acid 2-trimethylsilanyl-ethyl ester

(2S,3S)-3-(4-{2-Benzyloxycarbonyl-2-[(Z)-hydroxyimino]-acetyl}-phenoxy)-2-tert-butoxycarbonylamino-4-methyl-pentanoic acid 2-trimethylsilanyl-ethyl ester