Using O=C(c1ccc(Br)cc1)N1CCC2(CC1)OCCO2, C[Sn](C)(C)c1nccs1 to produce O=C(c1ccc(-c2nccs2)cc1)N1CCC2(CC1)OCCO2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.