Using O=C1CCC(=O)N1Br, CC(C)(C)OC(=O)Cc1cc(C(C)(C)C)c(O)c(C(C)(C)C)c1 to produce CC(C)(C)OC(=O)C(Br)c1cc(C(C)(C)C)c(O)c(C(C)(C)C)c1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.