Using CCCC[Sn](CCCC)(CCCC)c1ncco1, COC(=O)c1nc(Br)c(C(F)(F)F)cc1N to produce COC(=O)c1nc(-c2ncco2)c(C(F)(F)F)cc1N, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.