methyl (3S,7aS)-3-(tert-butyl)-7-hydroxy-6-methyl-5-oxo-1H,3H-pyrrolo[1,2-c]oxazole-7a(5H)-carboxylate

(3S,7aR)-methyl 7-((3R,4R)-5-(benzyloxy)-4-hydroxy-3-methylpentyl)-3-tert-butyl-6-methyl-5-oxo-1,3,5,7a-tetrahydropyrrolo[1,2-c]oxazole-7a-carboxylate

(3S,7aR)-methyl 7-((3R,4R)-5-(benzyloxy)-4-(tert-butyldimethylsilyloxy)-3-methylpentyl)-3-tert-butyl-6-methyl-5-oxo-1,3,5,7a-tetrahydropyrrolo[1,2-c]oxazole-7a-carboxylate

(3S,6S,7aR,E)-methyl 7-((3R,4R)-5-(benzyloxy)-4-(tert-butyldimethylsilyloxy)-3-methylpentylidene)-3-tert-butyl-6-methyl-5-oxohexahydropyrrolo[1,2-c]oxazole-7a-carboxylate

(3R,3aS,4S,6aS)-4-[(2R,3R)-4-(benzyloxy)-3-hydroxy-2-methylbutyl]-3a-hydroxy-6a-(hydroxymethyl)-3-methyldihydro-1H-furo[3,4-b]pyrrole-2,6(3H,4H)-dione