(2S,3S)-1-tert-butyl-2-methyl 3-hydroxypyrrolidine-1,2-dicarboxylate
(2S,3S)-1-(tert-butoxycarbonyl)-3-hydroxypyrrolidine-2-carboxylic acid
tert-butyl (2R,3S)-3-{[tert-butyl(dimethyl)silyl]oxy}-2-(hydroxymethyl)pyrrolidine-1-carboxylate
4-{2-[2-(tert-butoxycarbonyl-methyl-amino)-propionylamino]-3,3-dimethyl-butyryl}-3-(3,4-difluoro-phenoxymethyl)-hexahydro-pyrrolo[3,2-b]pyrrole-1-carboxylic acid benzy1 ester
4-(2-tert-butoxycarbonylamino-3,3-dimethyl-butyryl)-3-(3,4-difluorophenoxymethyl)-hexahydro-pyrrolo[3,2-b]pyrrole-1-carboxylic acid benzyl ester