Radical cross-coupling reactions represent a revolutionary tool to make C(sp³)–C and C(sp³)–heteroatom bonds by means of transition metals and photoredox or electrochemical approaches. However, the use of main-group elements to harness this type of reactivity has been little explored. Here we show how a low-valency bismuth complex is able to undergo one-electron oxidative addition with redox-active alkyl-radical precursors, mimicking the behaviour of first-row transition metals. This reactivity paradigm for bismuth gives rise to well-defined oxidative addition complexes, which could be fully characterized in solution and in the solid state. The resulting Bi(III)–C(sp³) intermediates display divergent reactivity patterns depending on the α-substituents of the alkyl fragment. Mechanistic investigations of this reactivity led to the development of a bismuth-catalysed C(sp³)–N cross-coupling reaction that operates under mild conditions and accommodates synthetically relevant NH-heterocycles as coupling partners.

自由基交叉偶联反应是通过过渡金属和光氧化还原或电化学方法形成 C( sp ³ )–C 和 C( sp ^{3 )– 杂原子键的革命性工具。}然而，使用主族元素来利用这种类型的反应性的探索却很少。在这里，我们展示了低价铋配合物如何能够与氧化还原活性烷基自由基前体进行单电子氧化加成，模仿第一行过渡金属的行为。铋的这种反应范式产生了明确的氧化加成络合物，可以在溶液和固态中对其进行充分表征。所得的 Bi(III)–C( sp ³ ) 中间体根据烷基片段的 α-取代基表现出不同的反应模式。对这种反应性的机理研究导致了铋催化的 C( sp ³ )-N 交叉偶联反应的发展，该反应在温和条件下进行，并容纳合成相关的 NH-杂环作为偶联伙伴。