3-{[(2R,3aS,5aR,6R,9aR,9bS)-5a,9b-dimethyl-7-methylene-2-(2-methylprop-1-enyl)dodecahydronaphtho[2,1-b]furan-6-yl]methyl}-2-methoxy-5,6-dimethyl-4H-pyran-4-one

3-{(1R,4aR,5S,6S,8aR)-5-[(R)-2-hydroxy-4-methylpent-3-enyl]-5,8a-dimethyl-2-methylene-6-(triethylsiloxy)decahydronaphthalen-1-yl}methyl-2-methoxy-5,6-dimethyl-4H-pyran-4-one