[{"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][C][=O][=C][Ring1][=Branch2][Br]>>[C][C][=Branch1][C][=O][C][=C][C][=C][C][Branch1][C][O][=C][Ring1][#Branch1][Br]"}, {"from": "gpt", "value": "[Br][P][Branch1][C][Br][Br].[C][O].[Cl][C][Cl]"}]