Using CCCC(C(C)C)C(C#N)C(=O)OC, CC(C)(C)OC(=O)CBr to produce CCCC(C(C)C)C(C#N)(CC(=O)OC(C)(C)C)C(=O)OC, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.