Using CCCCCC(C=O)c1ccc2c(c1)N(C(=O)OC(C)(C)C)CCC2(C)C, BrC(Br)(Br)Br to produce CCCCCC(C=C(Br)Br)c1ccc2c(c1)N(C(=O)OC(C)(C)C)CCC2(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.