Using COCOc1c(C)c(C)c2c(c1C)C(=O)CC1(CCC1)O2, COC=O to produce COCOc1c(C)c(C)c2c(c1C)C(=O)C(C=O)C1(CCC1)O2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.