Using Brc1ccc2nc3cc(Br)ccc3nc2c1, C=C(OCC)[Sn](CCCC)(CCCC)CCCC to produce C=C(OCC)c1ccc2nc3cc(C(=C)OCC)ccc3nc2c1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.