(1R,2R,4R,10R,11S,14S,15S,16S,18S,19S)-10,14-dimethylspiro[hexacyclo[9.8.0.0^{2,4}.0^{5,10}.0^{14,19}.0^{16,18}]nonadecane-15,2'-oxolan]-5-ene-5',7-dione
(1R,2R,4R,10R,11S,14S,15S,16S,18S,19S)-10,14-dimethylspiro[hexacyclo[9.8.0.02,4.05,10.014,19.016,18]nonadecane-15,2'-oxolan]-5-ene-5',7-dione
(1R,2R,4R,10R,11S,14S,15S,16S,18S,19S)-10,14-dimethylspiro[hexacyclo[9.8.0.0²,⁴.0⁵,¹⁰.0¹⁴,¹⁹.0¹⁶,¹⁸]nonadecane-15,2'-oxolan]-5-ene-5',7-dione