Using CC(=O)O, COc1cc2c(cc1OC)C(C)(CCC(=O)O)OCC2 to produce COc1cc2c(cc1OC)C(C)(CCC(=O)O)OCC2=O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.