Showing structure for 5-acetyl-3,10,10,14,18-pentamethyl-20-methylidene-9,17,19-trioxahexacyclo[9.7.1.1³,¹⁵.0¹,¹⁵.0⁵,¹⁴.0⁶,¹¹]icos-6-ene-2,8,12,16-tetrone