[H]O[C@@]1([H])C([H])=C([H])[C@]([H])(C([H])([H])[H])[C@@]2(C([H])([H])[H])C([H])([H])C3=C(C(=O)OC3=C([H])[C@]12O[H])C([H])([H])[H]