Using COC(=O)c1cc(Br)c(Cl)s1, CCCC[Sn](CCCC)(CCCC)c1cnnn1C to produce COC(=O)c1cc(-c2cnnn2C)c(Cl)s1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.