Using C[O-], O=C(c1ccc(Cl)cc1Cl)c1oc2cc(Br)ccc2c1CBr to produce COCc1c(C(=O)c2ccc(Cl)cc2Cl)oc2cc(Br)ccc12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.