Showing structure for (1as,3as,4r,5r,7r,7as,7br)-4,5,7a,7b-tetramethyl-4-[2-(5-oxo-2h-furan-3-yl)ethyl]-hexahydro-1ah-naphtho[1,2-b]oxiren-7-yl (2z)-2-methylbut-2-enoate