methyl (2S,4S)-1-(2,2-diphenylacetyl)-4-((R)-3-phenylpiperidin-1-yl)pyrrolidine-2-carboxylate

methyl (S)-1-(2,2-diphenylacetyl)-4-oxopyrrolidine-2-carboxylate

methyl (2S,4S)-4-((4aR,7aR)-6-benzyloctahydro-1H-pyrrolo[3,4-b]pyridin-1-yl)-1-(2,2-diphenylacetyl)pyrrolidine-2-carboxylate

(2S,4S)-4-((4aR,7aR)-6-benzoctahydro-1H-pyrrolo[3,4-b]pyridin-1-yl)-1-(2,2-diphenylacetyl)pyrrolidine-2-carboxylic acid

methyl (3S,3'S,5'S)-1'-(2,2-diphenylacetyl)-3-phenyl-[1,3'-bipyrrolidine]-5'-carboxylate