Using O=C([O-])[O-], CC(C)(C(=O)O)c1ccc(C(=O)CCCCl)cc1 to produce COC(=O)C(C)(C)c1ccc(C(=O)CCCCl)cc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.