Showing structure for (4s,4ar,5r,6s,8as)-3,4a,5-trimethyl-4-[(2-methylpropanoyl)oxy]-9-oxo-4h,5h,6h,7h,8h,8ah-naphtho[2,3-b]furan-6-yl (2z)-2-methylbut-2-enoate