Using Cc1oc2c(NC(=O)c3c(Cl)cccc3Cl)cccc2c1CCl, O=C([O-])[O-] to produce C=C1c2cccc(NC(=O)c3c(Cl)cccc3Cl)c2OC1(C)OC, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.