methyl (2S,3aR,3bR,6aS,7aS)-2,3,3a,3b,4,5,6,6a,7,7a-decahydro-2,3b-dimethyl-5-oxo-1H-cyclopentapentalene-2-carboxylate

methyl (1S,2aR,2bR,2cR,4S,5aR,5bS,5cS)-1-(benzoyloxy)-decahydro-4,5b-dimethyl-2-oxo-1H-cyclopenta[a]cyclopropa[cd]pentalene-4-carboxylate

methyl (2S,3aR,3bS,7aS)-2,3,3a,3b,4,5,7,7a-octahydro-2,3b-dimethyl-5-oxo-1H-cyclopentapentalene-2-carboxylate

methyl (2S,2aR,2bS,4S,5aR,6S,6aR)-decahydro-2-hydroxy-4,6-dimethyl-2,6-methanocyclobuta[a]pentalene-4-carboxylate

methyl [2S-(2α,3aα,3bβ,7aα)]-2,3,3a,3b,4,5,7,7a-octahydro-2,3b-dimethyl-4-[(dimethylamino)methyl]-5-oxo-1H-cyclopenta[a]pentalene-2-carboxylate