((3R,3aS,4S,6aS)-4-((2R,3R)-3-(ethanoyloxy)-4-hydroxy-2-methylbutyl)-3a-hydroxy-1,3-dimethyl-2,6-dioxohexahydro-1H-furo[3,4-b]pyrrol-6a-yl)methyl ethanoate

((3R,3aS,4S,6aS)-4-((2R,3R)-3-(ethanoyloxy)-2-methyl-4-oxobutyl)-3a-hydroxy-1,3-dimethyl-2,6-dioxohexahydro-1H-furo[3,4-b]pyrrol-6a-yl)methyl ethanoate

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

(3S,7aR)-methyl 7-((3R,4R,1E)-5-(benzyloxy)-4-hydroxy-3-methylpent-1-enyl)-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