(6aS,7aR,8R,9R,11aR,11bS)-5-Chloro-6a,7a,8,9,11a,11b-hexahydro-7a-hydroxy-3-[(1E,3R,4R)-4-hydroxy-3-methyl-1-penten-1-yl]-6a,8,9-trimethyl-6H,11H-pyrano[3′,4′:4,5]furo[2,3-h]-2-benzopyran-6,11-dione