Using CC(=O)O, COc1ccc(OC)c2c(OC)c(C(O)CCC(C)C)cc(OC)c12 to produce COc1ccc(OC)c2c(OC)c(C(CCC(C)C)OC(C)=O)cc(OC)c12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.