Using Cc1cc(C(C)(C)C)[se+]c(C(C)(C)C)c1, O=C1C(Cl)=C(Cl)C1(Cl)Cl to produce CC(C)(C)C1=CC(=CC2=C(Cl)C(=O)C2(Cl)Cl)C=C(C(C)(C)C)[Se]1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.