Using CC(O)(CC(=O)O)c1ccc(-c2ccc(Cl)c(Cl)c2)cc1 to produce CC(=CC(=O)O)c1ccc(-c2ccc(Cl)c(Cl)c2)cc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.