Using CCOC(=O)[C@H](CC(C)C)NC(=O)[C@@H](NC(=O)[C@@H](N)Cc1c[nH]c2ccccc12)C(C)(C)C, O=C(O)[C@@H]1CCCN1C(=O)OCc1ccccc1 to produce CCOC(=O)[C@H](CC(C)C)NC(=O)[C@@H](NC(=O)[C@H](Cc1c[nH]c2ccccc12)NC(=O)[C@@H]1CCCN1C(=O)OCc1ccccc1)C(C)(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.