Using O=C(C=P(c1ccccc1)(c1ccccc1)c1ccccc1)CBr, Sc1ccccc1 to produce O=C(C=P(c1ccccc1)(c1ccccc1)c1ccccc1)CSc1ccccc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.