Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, P. R. China.
School of Future Technology, University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
J Am Chem Soc. 2020 Sep 30;142(39):16805-16813. doi: 10.1021/jacs.0c07600. Epub 2020 Sep 17.
Transition-metal-catalyzed C-N bond-forming reactions have emerged as fundamental and powerful tools to construct arylamines, a common structure found in drug agents, natural products, and fine chemicals. Reported herein is an alternative access to heteroarylamine via radical-radical cross-coupling pathway, powered by visible light catalysis without any aid of external oxidant and reductant. Only by visible light irradiation of a photocatalyst, such as a metal-free photocatalyst, does the cascade single-electron transfer event for amines and heteroaryl nitriles occur, demonstrated by steady-state and transient spectroscopic studies, resulting in an amine radical cation and aryl radical anion in situ for C-N bond formation. The metal-free and redox economic nature, high efficiency, and site-selectivity of C-N cross-coupling of a range of available amines, hydroxylamines, and hydrazines with heteroaryl nitriles make this protocol promising in both academic and industrial settings.
过渡金属催化的 C-N 键形成反应已成为构建芳基胺的基本且强大的工具，芳基胺是药物制剂、天然产物和精细化学品中常见的结构。本文报道了一种通过自由基-自由基交叉偶联途径获得杂芳基胺的替代方法，该方法无需任何外加氧化剂和还原剂，仅通过可见光催化即可实现。只有可见光照射光催化剂（如无金属光催化剂），才能发生胺和杂芳基腈的级联单电子转移反应，这通过稳态和瞬态光谱研究得到了证实，从而原位生成胺自由基阳离子和芳基自由基阴离子，用于 C-N 键形成。该方法具有无金属、氧化还原经济性、高效率和位点选择性，可实现一系列可用的胺、羟胺和肼与杂芳基腈的 C-N 交叉偶联，因此在学术和工业领域都具有广阔的应用前景。
