Using FC(F)CBr, CC(=O)c1cc2c(-c3cc(C(C)(C)C)cc(C(C)(C)C)c3O)cccc2s1 to produce CC(=O)c1cc2c(-c3cc(C(C)(C)C)cc(C(C)(C)C)c3OCC(F)F)cccc2s1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.