Using OCc1ccc(F)cc1, O=C1OC(=O)c2c(F)c(F)c(F)c(F)c21 to produce O=C(O)c1cc(OCc2ccc(F)cc2)c(F)c(F)c1F, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.