[H]O[C@]1(C([H])=C([H])C(=O)C(=C1[H])[C@@]1(C([H])([H])[H])C([H])([H])C([H])([H])C([H])([H])C1(C([H])([H])[H])C([H])([H])[H])C([H])([H])[H]