Using C[C@H](CO)[C@@H](c1ccco1)N(C)C(=O)OC(C)(C)C, O=C(O)CBr to produce C[C@H](COCC(=O)O)[C@@H](c1ccco1)N(C)C(=O)OC(C)(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.