methyl (2S,4aS,6aS,9aR)-1,2,4,4a,6a,7,8,9-octahydro-2-methoxy-8,8-dimethylpentaleno<1,6a-c>pyran-5-carboxylate

(2aR,4aR,7aR)-2a-Hydroxymethyl-6,6-dimethyl-2-methylene-hexahydro-cyclobuta[c]pentalen-3-one

(3aS,5aS,8aS)-3a,7,7-Trimethyl-tetrahydro-pentaleno[1,6a-b]furan-2,4-dione

(4aR,6aS,9aS)-8,8-Dimethyl-hexahydro-pentaleno[1,6a-c]pyridine-2,5-dione