[H]O[C@@]1([H])C2=C([H])C(=O)[C@@]([H])(C(=C([H])[H])C([H])([H])[H])C([H])([H])[C@]2(C([H])([H])[H])[C@@]([H])(C([H])([H])[H])C([H])([H])[C@@]1([H])O[H]