Using O=C(O)C(Br)Br, Cc1cc(O)c(O)cc1S(=O)(=O)c1ccc(Br)cc1 to produce Cc1cc2c(cc1S(=O)(=O)c1ccc(Br)cc1)OC(C(=O)O)O2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.