[H]O[C@]1([H])C([H])=C([H])[C@@]2(C(=O)O[C@]3([H])C([H])=C4C(=C([H])C(=O)OC4([H])[H])[C@]1(C([H])([H])[H])[C@]23[H])C([H])([H])[H]