1-tert-butyl 2-methyl (2S,4S)-4-[(tert-butyldimethylsilyl)oxy]-5-oxopyrrolidine-1,2-dicarboxylate

(2S,4R)-4-(4-Chloro-naphthalen-1-yloxy)-5-hydroxy-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester

(2S,4S)-N-((S)-1-(2-chlorophenyl)-2-((3,3-difluorocyclobutyl)amino)-2-oxoethyl)-1-(4-cyanopyridin-2-yl)-N-(3,5-difluorophenyl)-4-hydroxy-5-oxopyrrolidine-2-carboxamide

methyl (4S)-cis-N-Boc-4-hydroxyl pyroglutamate

(2S,4R)-4-(4-Chloro-naphthalen-1-yloxy)-5-oxo-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester

(2S,4R)-5-Acetoxy-4-(4-chloro-naphthalen-1-yloxy)-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester