Using O=C1CCC(=O)N1Br, COC(=O)c1ccc(C)cc1O[Si](C)(C)C(C)(C)C to produce COC(=O)c1ccc(CBr)cc1O[Si](C)(C)C(C)(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.