Showing structure for (3ar,4s,4as,5s,8s,8ar,9as)-4-(acetyloxy)-8a-methyl-3-methylidene-2-oxo-octahydrospiro[naphtho[2,3-b]furan-5,2'-oxiran]-8-yl (2s,3s)-2,3-dimethyloxirane-2-carboxylate