Using O=C(O)c1ccc(Br)cc1Cl, CC(C)(C)OC(=O)c1ccc(Br)cc1Cl to produce C=Cc1ccc(C(=O)OC(C)(C)C)c(Cl)c1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.