Using CCOC(=O)C(C)(C)N1COC(C)=C(I)C1=O, CCCC[Sn](CCCC)(CCCC)c1cccs1 to produce CCOC(=O)C(C)(C)N1COC(C)=C(c2cccs2)C1=O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.