Despite their significant importance to numerous fields, the difficulties in direct and diverse synthesis of α-hydroxy-γ-lactams pose substantial obstacles to their practical applications. Here, we designed a nitrogen and TiO₂ co-doped graphitic carbon-supported material with atomically dispersed cobalt sites (Co_SA-N/NC-TiO₂), which was successfully applied as a multifunctional catalyst to establish a general method for direct construction of α-hydroxy-γ-lactams from cheap and abundant nitro(hetero)arenes, aldehydes, and H₂O with alkynoates. The striking features of operational simplicity, broad substrate and functionality compatibility (>100 examples), high step and atom efficiency, good selectivity, and exceptional catalyst reusability highlight the practicality of this new catalytic transformation. Mechanistic studies reveal that the active CoN₄ species and the dopants exhibit a synergistic effect on the formation of key acid-masked nitrones; their subsequent nucleophilic addition to the alkynoates followed by successive reduction, alkenyl hydration, and intramolecular ester ammonolysis delivers the desired products. In this work, the concept of reduction interruption leading to new reaction route will open a door to further develop useful transformations by rational catalyst design.

中文翻译：

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通过单原子钴催化剂选择性获得功能性 γ-内酰胺的多组分还原偶联

尽管α-羟基-γ-内酰胺对许多领域具有重要意义，但直接和多样化合成α-羟基-γ-内酰胺的困难对其实际应用造成了巨大障碍。在这里，我们设计了一种氮和TiO ₂共掺杂的具有原子分散钴位点的石墨碳负载材料（Co _SA -N/NC-TiO ₂），并成功应用于多功能催化剂，建立了直接构建的通用方法从廉价且丰富的硝基（杂）芳烃、醛和 H ₂ O 与炔酸酯合成 α-羟基-γ-内酰胺。操作简单性、广泛的底物和功能兼容性（> 100 个示例）、高步骤和原子效率、良好的选择性以及出色的催化剂可重复使用性等显着特征突出了这种新催化转化的实用性。机理研究表明，活性CoN ₄物质和掺杂剂对关键酸掩蔽硝酮的形成表现出协同作用；它们随后与炔酸酯进行亲核加成，然后连续还原、烯基水合和分子内酯氨解，得到所需的产物。在这项工作中，还原中断导致新的反应路线的概念将为通过合理的催化剂设计进一步开发有用的转化打开一扇门。