Showing structure for methyl 6,15-bis(acetyloxy)-4,5,7,10,14,14-hexamethyl-8,18-dioxo-19-oxapentacyclo[10.5.2.0¹,¹³.0²,¹⁰.0⁵,⁹]nonadeca-3,6-diene-9-carboxylate