Using O=C(CBr)c1ccc(Cl)cc1Cl, CC1(C)OCC(COC(F)(F)C(F)F)O1 to produce FC(F)C(F)(F)OCC1COC(CBr)(c2ccc(Cl)cc2Cl)O1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.