Using CCOC(=O)CCc1c(C)cc(Cl)c2c1C(Cl)C(Cl)(Cl)CC2 to produce CCOC(=O)CCc1c(C)cc(Cl)c2c1C=C(Cl)CC2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.