Using BrC(Br)(Br)Br, COc1cc(C)c2c(ccn2C(=O)OC(C)(C)C)c1C=O to produce COc1cc(C)c2c(ccn2C(=O)OC(C)(C)C)c1C=C(Br)Br, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.