Using BrC(Br)(Br)Br, CC(C)(C)OC(=O)N1C(C)(C)OC[C@@]1(C)C=O to produce CC(C)(C)OC(=O)N1C(C)(C)OC[C@]1(C)C=C(Br)Br, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.