Using COc1cc2c(c(OC)c1)[C@H]1CC[C@]3(C)C(=O)CC[C@H]3[C@H]1CC2, CCO to produce COc1cc2c(c(OC)c1)[C@H]1CC[C@]3(C)[C@@H](OC(C)=O)CC[C@H]3[C@H]1CC2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.