Using COc1c(C=C2CCN(C(=O)OC(C)(C)C)CC2)cc(Br)cc1[N+](=O)[O-] to produce CC(C)(C)OC(=O)N1CCC(=Cc2cc(Br)cc([N+](=O)[O-])c2O)CC1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.