Using C[C@@H](c1ccc(Br)cc1)N1CCC2(CCC3(CC2)OCC(C)(C)CO3)OC1=O to produce C[C@@H](c1ccc(Br)cc1)N1CCC2(CCC(=O)CC2)OC1=O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.