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