Using CC(C)(C)c1cc(SC[C@@H]2C[C@@H](O)CC(=O)O2)cc(C(C)(C)C)c1O, O=C(O)CC(O)(CC(=O)O)C(=O)O to produce CC(C)(C)c1cc(SC[C@@H](O)C[C@@H](O)CC(=O)O)cc(C(C)(C)C)c1O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.