Using O=C(O)CC12CC3CC(C1)CC(c1ccccc1)(C3)C2, COC(=O)CC12CC3CC(CC(Br)(C3)C1)C2 to produce COC(=O)CC12CC3CC(C1)CC(c1ccccc1)(C3)C2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.