Using CC(C)(C)C(=O)OCCl, Cc1c(CC(=O)O)cccc1C(=O)c1ccc(Cl)cc1 to produce Cc1c(CC(=O)OCOC(=O)C(C)(C)C)cccc1Cc1ccc(Cl)cc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.