Using CC1(C)CCC(C)(C)c2cc(I)c(O)cc21, O=C(CBr)c1ccc(Br)s1 to produce CC1(C)CCC(C)(C)c2cc(OCC(=O)c3ccc(Br)s3)c(I)cc21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.