[{"from": "human", "value": "Given this chemical reaction, what are some reagents that could have been used? [C][O][C][=C][C][=C][C][Branch1][#Branch1][C][=Branch1][C][=O][C][Br][=C][Ring1][#Branch2]>>[O][=C][Branch1][Ring1][C][Br][C][=C][C][=C][C][Branch1][C][O][=C][Ring1][#Branch1]"}, {"from": "gpt", "value": "[Br][B][Branch1][C][Br][Br].[Cl][C][Cl]"}]