Using CCOC(=O)c1cncc(Br)c1, CCCC[Sn](CCCC)(CCCC)c1c(F)cccc1F to produce CCOC(=O)c1cncc(-c2c(F)cccc2F)c1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.