Showing structure for (2r,5r,7's,9's,13'r)-5,7',9',13'-tetramethyl-5'-oxaspiro[oxane-2,6'-pentacyclo[10.8.0.0²,⁹.0⁴,⁸.0¹³,¹⁸]icosane]-14',17'-dien-16'-one