(3S)-3a,5aα,7,8,9,10,10aβ,10cα-Octahydro-3-hydroxy-8β-hydroxyacetyl-3aα,8-dimethyl-4H-3,10bβ-ethano-1H,3H-benzo[h]furo[4,3,2-de]-2-benzopyran-4-one