Using COC(=O)C(Cl)(Cl)C12CC3CC(CC(O)(C3)C1)C2 to produce O=C(O)C(Cl)(Cl)C12CC3CC(CC(O)(C3)C1)C2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.