Using Cc1ccc(-c2ccc3c(c2)C=C(CO)CCO3)cc1, BrC(Br)(Br)Br to produce Cc1ccc(-c2ccc3c(c2)C=C(CBr)CCO3)cc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.