Using O=C1CCC(=O)N1Br, COCO[C@@H]1Cc2ccccc2[C@H]1N(COC)C(=O)OC(C)(C)C to produce COCO[C@@H]1C(Br)c2ccccc2[C@H]1N(COC)C(=O)OC(C)(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.