Using O=Cc1cc(I)sc1CO, CCCC[Sn](CCCC)(CCCC)c1ccc(-c2cccs2)s1 to produce O=Cc1cc(-c2ccc(-c3cccs3)s2)sc1CO, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.