Using O=CCCc1c(Cl)cc(Cl)c2ccc(Cl)cc12, COC(=O)CC(C)=O to produce COC(=O)CC(=O)CC(O)CCc1c(Cl)cc(Cl)c2ccc(Cl)cc12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.