Using COC(=O)[C@@H](NC(=O)OC(C)(C)C)C(C)(C)S, BrCCc1ccccc1 to produce COC(=O)[C@@H](NC(=O)OC(C)(C)C)C(C)(C)SCCc1ccccc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.