C=C1[C@@H](OC(C)=O)[C@@H]2[C@](C)(C(=O)C(O)=C3C(C)(C)C(=O)C[C@@H](O)[C@]32C)[C@@H]2C(=O)O[C@](C)(C(=O)OC)C(=O)[C@]12C aspertermeroterpene B