Using CC(C)(C)OC(=O)N[C@@H](CC(=O)O)c1ccccc1, O=C([O-])[O-] to produce COC(=O)C[C@H](NC(=O)OC(C)(C)C)c1ccccc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.