Using COCC(C(=O)OC)c1cc(Cl)cc(Cl)c1, C=C(Oc1cc(Cl)cc(Cl)c1)C(=O)O to produce COCC(Oc1cc(Cl)cc(Cl)c1)C(=O)O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.