C[C@H]1CC[C@@H]2[C@@H](C[C@H](C)C(=O)/C=C/[C@]3(C)C[C@@](O)(C1)OO3)C2(C)C (1R,3S,6R,8R,10S,12E,14S)-1-hydroxy-3,7,7,10,14-pentamethyl-15,16-dioxatricyclo[12.2.1.0^{6,8}]heptadec-12-en-11-one