Using O=C1OC(=O)c2cc(Cl)c(Cl)cc21, Oc1ccc(Cl)c(O)c1 to produce Clc1cc2c(c(-c3ccccc3)c1Cl)Cc1ccccc1O2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.