Using C[Sn](C)(C)c1cc(C=O)c2c(c1)oc1ccccc12, O=S(=O)([O-])[O-] to produce C[Sn](C)(C)c1cc(C(=O)O)c2c(c1)oc1ccccc12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.