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