[{"from": "human", "value": "What reagents could have been utilized in the following chemical reaction? [I][I].[N][C][=C][C][=C][Branch1][Ring2][C][C][O][C][=C][Ring1][=Branch2]>>[N][C][=C][C][=C][Branch1][Ring2][C][C][O][C][=C][Ring1][=Branch2][I]"}, {"from": "gpt", "value": "[C][O].[O][=C][Branch1][C][O-1][O-1].[Ca+2]"}]