Using BrC(Br)(Br)Br, COC(=O)[C@H](CCO)NC(=O)OC(C)(C)C to produce COC(=O)[C@H](CCBr)NC(=O)OC(C)(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.