(4aS,6aS,12bS)-2H-9,10-dibenzyloxy-11-chloro-1,3,4,4a,5,6,6a,12b-octahydro-6a-[(phenylseleno)methyl]-4,4,12b-trimethyl-benzo[a]xanthene

(1S,4aS,8aS)-3H-2-methylene-1,4,4a,5,6,7,8,8a-octahydro-5,5,8a-trimethylnaphthalene-1-carboxaldehyde