Using O=C1CCC(=O)N1Br, COC(=O)[C@H]1C[C@@H](CCO)CN1C(=O)OC(C)(C)C to produce COC(=O)[C@H]1C[C@@H](CCBr)CN1C(=O)OC(C)(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.