Using COCC1CC(C(=O)OC)N(C(=O)OC(C)(C)C)C1, O=C(CBr)c1ccc(Br)cc1 to produce COCC1CC(C(=O)OCC(=O)c2ccc(Br)cc2)N(C(=O)OC(C)(C)C)C1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.