Synthesis of phenanthridin-6(5H)-ones was achieved via copper-catalyzed cyclization of 2-phenylbenzamides using air as the oxidant and KOt-Bu as the base. It was discovered that, besides Ph3P, other ligands such as 1,10-phenanthroline, TMEDA as well as l -proline could also be used as the ligand to effect the transformation.

中文翻译：

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通过铜催化环化 2-苯基苯甲酰胺合成 Phenanthridin-6(5H)-ones

以空气为氧化剂，以 KOt-Bu 为碱，通过铜催化环化 2-苯基苯甲酰胺，合成了 phenanthridin-6(5H)-ones。发现除了Ph3P之外，其他配体如1,10-菲咯啉、TMEDA以及l-脯氨酸也可用作实现转化的配体。