[{"from": "human", "value": "What reagents could have been utilized in the following chemical reaction? [Br][C][C][C][C][C][C][Br].[C][O]>>[C][O][C][C][C][C][C][C][Br]"}, {"from": "gpt", "value": "[C][C][C][C][C][C].[C][O-1].[O].[Na+1]"}]