Using COC(=O)c1sc(-c2ccc(Cl)cc2)cc1Br, CCCCC([Sn])=C(CCCC)CCCC to produce C=Cc1cc(-c2ccc(Cl)cc2)sc1C(=O)OC, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.