Using COC(=O)[C@H](Cc1ccc(OC(C)(C)C)cc1)NC(=O)[C@@H](N)C(C)C, CC(C)(C)OC(=O)CC[C@@H](NC(=O)OCc1ccccc1)C(=O)O to produce COC(=O)[C@H](Cc1ccc(OC(C)(C)C)cc1)NC(=O)[C@@H](NC(=O)[C@@H](CCC(=O)OC(C)(C)C)NC(=O)OCc1ccccc1)C(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.