Using C=O, COC(=O)C1COc2cc(OCc3ccc(Cl)cc3Cl)ccc21 to produce COC(=O)C1(CO)COc2cc(OCc3ccc(Cl)cc3Cl)ccc21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.