Using O, CC(C)(C)OC(=O)N1C(=O)[C@@H]2C[C@H]1CC[C@@H]2N1CC[C@H](NC(=O)OCc2ccccc2)C1=O to produce CC(C)(C)OC(=O)N[C@@H]1CC[C@H](N2CC[C@H](NC(=O)OCc3ccccc3)C2=O)[C@H](C(=O)O)C1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.