Using CCCCCc1ccc(-c2ccc(CC[C@H]3CC[C@H](C=O)CC3)cc2)cc1, BrC(Br)(Br)Br to produce CCCCCc1ccc(-c2ccc(CC[C@H]3CC[C@H](C=C(Br)Br)CC3)cc2)cc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.