(S)-4-((((9H-Fluoren-9-yl)methoxy)carbonyl)amino)-5-methoxy-5-oxopentanoic acid

(2S)-2-(1,3-dioxo-1,3-dihydroisoindol-2-yl)pentanedioic acid α-methyl ester

(S)-6-diazo-5-oxo-2-(2,2,2-trifluoro-acetylamino)-hexanoic acid ethyl ester

(S)-4-Chlorcarbonyl-2-(trifluor-acetylamino)butansaeureethylester