Showing structure for (4ar,5s,6r,8ar,9as)-5-(acetyloxy)-9a-hydroxy-3,5,8a-trimethyl-2-oxo-4h,4ah,6h,7h,8h,9h-naphtho[2,3-b]furan-6-yl (2s,3r)-2,3-dimethyloxirane-2-carboxylate