Using O=C1CCC(=O)N1Br, CC(C)(C)OC(=O)[C@H](CCCO)NC(=O)OCC[Si](C)(C)C to produce CC(C)(C)OC(=O)[C@H](CCCBr)NC(=O)OCC[Si](C)(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.