Using BrC(Br)(Br)Br, COc1ccc(C(O)[C@@H]2CN(C(=O)OC(C)(C)C)CCO2)cn1 to produce COc1ccc(C(Br)[C@@H]2CN(C(=O)OC(C)(C)C)CCO2)cn1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.