Catalytically Relevant Organocopper(III) Complexes Formed through Aryl-Radical-Enabled Oxidative Addition

Wenhao Yan, Andrew T. Poore, Lingfeng Yin, Samantha Carter, Yeu Shiuan Ho, Chao Wang, Stephen C. Yachuw, Yu Ho Cheng, Jeanette A. Krause, Mu Jeng Cheng, Shiyu Zhang, Shiliang Tian, Wei Liu

研究成果: Article同行評審

10 引文 斯高帕斯(Scopus)

摘要

Stepwise oxidative addition of copper(I) complexes to form copper(III) species via single electron transfer (SET) events has been widely proposed in copper catalysis. However, direct observation and detailed investigation of these fundamental steps remain elusive owing largely to the typically slow oxidative addition rate of copper(I) complexes and the instability of the copper(III) species. We report herein a novel aryl-radical-enabled stepwise oxidative addition pathway that allows for the formation of well-defined alkyl-CuIII species from CuI complexes. The process is enabled by the SET from a CuI species to an aryl diazonium salt to form a CuII species and an aryl radical. Subsequent iodine abstraction from an alkyl iodide by the aryl radical affords an alkyl radical, which then reacts with the CuII species to form the alkyl-CuIII complex. The structure of resultant [(bpy)CuIII(CF3)2(alkyl)] complexes has been characterized by NMR spectroscopy and X-ray crystallography. Competition experiments have revealed that the rate at which different alkyl iodides undergo oxidative addition is consistent with the rate of iodine abstraction by carbon-centered radicals. The CuII intermediate formed during the SET process has been identified as a four-coordinate complex, [CuII(CH3CN)2(CF3)2], through electronic paramagnetic resonance (EPR) studies. The catalytic relevance of the high-valent organo-CuIII has been demonstrated by the C-C bond-forming reductive elimination reactivity. Finally, localized orbital bonding analysis of these formal CuIII complexes indicates inverted ligand fields in σ(Cu-CH2) bonds. These results demonstrate the stepwise oxidative addition in copper catalysis and provide a general strategy to investigate the elusive formal CuIII complexes.

原文English
頁(從 - 到)15176-15185
頁數10
期刊Journal of the American Chemical Society
146
發行號22
DOIs
出版狀態Published - 2024 6月 5

All Science Journal Classification (ASJC) codes

  • 催化
  • 一般化學
  • 生物化學
  • 膠體和表面化學

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