[{"from": "human", "value": "Please suggest some possible reagents that could have been used in the following chemical reaction. [Br][Br].[O][C][=C][C][=C][C][Branch1][C][Cl][=C][Ring1][#Branch1]>>[O][C][=C][C][Branch1][C][Cl][=C][C][=C][Ring1][#Branch1][Br]"}, {"from": "gpt", "value": "[Cl][C][Cl].[O]"}]