[{"from": "human", "value": "From the provided chemical reaction, propose some possible reagents that could have been used. [C][O][C][=C][C][Branch1][C][I][=C][C][Branch1][Ring1][O][C][=C][Ring1][=Branch2][Cl]>>[O][C][=C][C][Branch1][C][I][=C][C][Branch1][C][O][=C][Ring1][Branch2][Cl]"}, {"from": "gpt", "value": "[Br][B][Branch1][C][Br][Br].[Cl][C][Cl].[O]"}]