Using CCCC[Sn](C=COCC)(CCCC)CCCC, COC(=O)c1nc(Cl)cc(Cl)c1Cl to produce COC(=O)c1nc(C(C)=O)cc(Cl)c1Cl, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.