[{"from": "human", "value": "From the provided chemical reaction, propose some possible reagents that could have been used. [C][O][C][=Branch1][C][=O][C][C][C][C][C][C][C][C][C][C][Br]>>[O][C][C][C][C][C][C][C][C][C][C][C][Br]"}, {"from": "gpt", "value": "[C][O][C][C][O][C][C][O][C].[Al+3].[BH4-1].[Cl-1].[Cl-1].[Cl-1].[Na+1]"}]