Using COC(=O)N(c1ccccc1)c1ccc2cccc(Br)c2n1, C=C(OCC)[Sn](CCCC)(CCCC)CCCC to produce COC(=O)N(c1ccccc1)c1ccc2cccc(C(C)=O)c2n1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.