Using COc1cc2c(c(OC)c1)[C@]1(C)CC[C@H]3C(C)(C)[C@@H](O)CC[C@]3(C)[C@H]1C2 to produce COc1cc2c(c(OC)c1)[C@]1(C)CC[C@H]3C(C)(C)C(=O)CC[C@]3(C)[C@H]1C2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.