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

methyl 2,3b,4-trimethyl-5-oxo-4-(phenylselanyl)-2,3,3a,3b,4,5,7,7a-octahydro-1H-cyclopenta[a]pentalene-2-carboxylate