Using COc1cc(C)cc2c1Oc1ccc(C(=O)CC(C)C)c(OC)c1C(=O)OC2, C[Mg]Br to produce COc1cc(C)cc2c1Oc1ccc(C(C)(O)CC(C)C)c(OC)c1C(=O)OC2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.