Using CC[Mg]Cl, COC(=O)[C@@H]1CCC(OC(C)=O)N1C(=O)OC(C)(C)C to produce CC[C@@H]1CC[C@@H](C(=O)OC)N1C(=O)OC(C)(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.