Toyama Yoshifumi, Yagi Akiko, Itami Kenichiro, Ito Hideto
Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, Japan.
Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, Japan.
Nat Commun. 2025 May 30;16(1):5044. doi: 10.1038/s41467-025-60318-y.
Birch reduction is a well-known process for transforming aromatic compounds. The reduction of aromatic rings using alkali metals produces anionic species that react with protons or electrophiles. Generally, this reaction is accompanied by significant limitations in the available nucleophiles, since in most cases only alkyl halides and silyl chlorides are available. In particular, the arylation of unfunctionalized polycyclic aromatic hydrocarbons (PAHs), so-called Birch reductive arylation, has not yet been investigated. Herein, we report a Birch reductive arylation by mechanochemical anionic activation using a lithium(0) wire, followed by addition of various fluoroarenes. Specifically, not only Birch reductive arylation products but also formal C-H arylation products can be obtained from unfunctionalized PAHs, achieving one-pot annulative π-extension to give nanographenes. This process is a unique reaction that is rarely achieved in solution, and shows the interesting reactivity of lithium metal and fluoroarenes in the solid state.
Birch还原是一种用于转化芳香族化合物的著名方法。使用碱金属还原芳香环会产生与质子或亲电试剂反应的阴离子物种。通常，该反应在可用亲核试剂方面存在显著限制，因为在大多数情况下，只有烷基卤化物和硅氯化合物可用。特别是，未官能化的多环芳烃（PAHs）的芳基化，即所谓的Birch还原芳基化，尚未得到研究。在此，我们报道了一种通过使用锂（0）丝进行机械化学阴离子活化，随后添加各种氟芳烃的Birch还原芳基化反应。具体而言，不仅可以从未官能化的PAHs中获得Birch还原芳基化产物，还可以获得形式上的C-H芳基化产物，实现一锅法环化π-扩展以得到纳米石墨烯。该过程是一种在溶液中很少实现的独特反应，并且展示了锂金属和氟芳烃在固态下有趣的反应性。
