Using CCOC(=O)Cc1c(-c2ccccc2)c2cc(CO)c(CO)cc2oc1=O to produce CCOC(=O)Cc1c(-c2ccccc2)c2cc3c(cc2oc1=O)C(=O)OC3, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.