C(sp³)‑CF₃ Reductive Elimination from a Five-Coordinate Neutral Copper(III) Complex

The reductive elimination from a high-valent late-transition-metal complex for the formation of a carbon–carbon or carbon–heteroatom bond represents a fundamental product-forming step in a number of catalytic processes. While reductive eliminations from well-defined Pt­(IV), Pd­(IV), Ni­(III)/Ni­(IV), and Au­(III) complexes have been studied, the analogous reactions from neutral Cu­(III) complexes remain largely unexplored. Herein, we report the isolation of a stable, five-coordinate, neutral square pyramidal Cu­(III) complex that gives CH3-CF3 in quantitative yield via reductive elimination. Mechanistic studies suggest that the reaction occurs through a synchronous bond-breaking/bond-forming process via a three-membered ring transition state.从高价后过渡金属配合物出发的还原消除反应，用于构建碳-碳或碳-杂原子键，是众多催化过程中核心的产物生成步骤。尽管针对结构明确的Pt(IV)、Pd(IV)、Ni(III)/Ni(IV)及Au(III)配合物的还原消除反应已有广泛研究，但中性Cu(III)配合物参与的同类反应仍基本未被探索。在此，我们成功分离得到一种稳定的五配位中性四方锥构型Cu(III)配合物，该配合物可通过还原消除反应以定量产率生成CH3-CF3。机理研究表明，该反应经由三元环过渡态，通过同步断键与成键的协同过程完成。