N-Cbz-(D)-Ala-(L)-Leu-O-tBu

D-Ala-L-Leu-O-tBu

(2S,3R)-N-tert-butoxycarbonyl-2-methyl-3-amino-4-hydroxy methyl butanoate

(2R,3S)-2-(tert-butoxycarbonyl)amino-3-methoxycarbonyl-3-methylbutanal

(2R,3S)-2-Amino-3-methyl-N-[(S)-1-(2,2,2-trichloro-ethoxycarbonyl)-ethyl]-succinamic acid methyl ester