[{"from": "human", "value": "What reagents could have been utilized in the following chemical reaction? [C][C][Branch1][C][Cl][C][=Branch1][C][=O][Cl].[O][C][C][O]>>[C][C][Branch1][C][Cl][C][=Branch1][C][=O][O][C][C][O]"}, {"from": "gpt", "value": "[C][C][O][C][C]"}]