Using CCCC[Sn](CCCC)(CCCC)c1ccco1, CCCc1nc2cc(Br)cc(C)c2[nH]1 to produce CCCc1nc2cc(-c3ccco3)cc(C)c2[nH]1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.