5-benzyloxy-4-oxo-pentanoic acid methyl ester

(4S,8aR)-8a-benzyloxymethyl-4-phenyltetrahydro-pyrrolo[2,1c][1,4]oxazine-1,6-dione

(3R,7aR)-dimethyl 3-acetyl-3-methyl-5-oxohexahydropyrrolo[1,2-c]oxazole-6,7a-dicarboxylate