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