Using FC(F)(F)c1ccc(S)cc1, CC(C)(C)OC(=O)N[C@@H](CCC(=O)O)C(=O)OCc1ccccc1 to produce CC(C)(C)OC(=O)N[C@@H](CCC(=O)Sc1ccc(C(F)(F)F)cc1)C(=O)OCc1ccccc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.