[{"from": "human", "value": "Based on the given chemical reaction, can you propose some likely reagents that might have been utilized? [Br][Br].[C][O][C][=Branch1][C][=O][C][C][Branch1][C][C][=O]>>[C][O][C][=Branch1][C][=O][C][C][=Branch1][C][=O][C][Br]"}, {"from": "gpt", "value": "[C][C][C][C][Cl].[O]"}]