(1S,7aS)-2-(tert-butoxycarbonyl)-6-oxo-2,3,3a,6,7,7a-hexahydro-1H-isoindole-1-carboxylic acid

2-(tert-butyl) 1-methyl (1S,7aS)-6-oxo-1,3,5,6,7,7a-hexahydro-2H-isoindole-1,2-dicarboxylate

(2S,3S,4S)-3-Carboxymethyl-4-(1-methyl-2-oxo-ethyl)-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester

(1S,3aS,7aS)-2-(tert-butoxycarbonyl)-6-oxo-2,3,3a,6,7,7a-hexahydro-1H-isoindole-1,3a-dicarboxylic acid

2-(tert-butyl) 1-methyl (1S,3aR,7aS)-4-methyl-6-((trimethylsilyl)oxy)-1,3,3a,4,7,7a-hexahydro-2H-isoindole-1,2-dicarboxylate