Using CCCC[Sn](CCCC)(CCCC)c1nccs1, COC(=O)c1occ(Br)c(=O)c1OCc1ccccc1 to produce COC(=O)c1occ(-c2nccs2)c(=O)c1OCc1ccccc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.