Using CC(=O)OCC1=C(C(=O)O)N2C(=O)[C@@H](N)[C@H]2SC1, C=C(C)C to produce CC(=O)OCC1=C(C(=O)OC(C)(C)C)N2C(=O)[C@@H](N)[C@H]2SC1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.