Using COC(=O)C1CC(C(=O)OC)C(C(F)(F)C(F)(F)Br)C1, O=S([O-])S(=O)[O-] to produce COC(=O)C1CC(C(=O)OC)C(C(F)(F)C(F)(F)S(=O)[O-])C1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.