Tan Chang-Yin, Hong Sungwoo
Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea.
Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Korea.
Nat Commun. 2024 Aug 13;15(1):6965. doi: 10.1038/s41467-024-51376-9.
Persistent radicals facilitate numerous selective radical coupling reactions. Here, we have identified acyl triazole as a new and versatile moiety for generating persistent radical intermediates through single-electron transfer processes. The efficient generation of these persistent radicals is facilitated by the formation of substrate-coordinated cobalt complexes, which subsequently engage in radical cross-coupling reactions. Remarkably, triazole-coordinated cobalt complexes exhibit metal-hydride hydrogen atom transfer (MHAT) capabilities with alkenes, enabling the efficient synthesis of diverse ketone products without the need for external ligands. By leveraging the persistent radical effect, this catalytic approach also allows for the development of other radical cross-coupling reactions with two representative radical precursors. The discovery of acyl triazoles as effective substrates for generating persistent radicals and as ligands for cobalt catalysis, combined with the bifunctional nature of the cobalt catalytic system, opens up new avenues for the design and development of efficient and sustainable organic transformations.
持久性自由基促进了众多选择性自由基偶联反应。在此，我们已确定酰基三唑是一种新型且通用的基团，可通过单电子转移过程生成持久性自由基中间体。底物配位钴配合物的形成促进了这些持久性自由基的高效生成，随后这些配合物参与自由基交叉偶联反应。值得注意的是，三唑配位钴配合物对烯烃具有金属氢化物氢原子转移（MHAT）能力，能够在无需外部配体的情况下高效合成多种酮产物。通过利用持久性自由基效应，这种催化方法还允许开发与两种代表性自由基前体的其他自由基交叉偶联反应。酰基三唑作为生成持久性自由基的有效底物以及钴催化的配体的发现，与钴催化体系的双功能性质相结合，为高效且可持续的有机转化的设计与开发开辟了新途径。
