Zhu S Hui, Wu Yu, Mao Jianyou, Xu Jingkai, Walsh Patrick J, Shi Hang
Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang Province 310058, China.
Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
Chem Soc Rev. 2025 Mar 3;54(5):2520-2542. doi: 10.1039/d4cs00466c.
Benzylic C-H functionalization is a valuable tool to make complex aromatic molecules from simple, readily available alkylbenzenes. While methods that involve benzylic radicals or cations generated by hydrogen atom transfer or oxidation have been well demonstrated, they often require oxidative conditions. In contrast, deprotonation methods offer a complementary approach to transform benzylic C-H bonds through a benzylic carbanion generated by deprotonation. Electrophilic transition metal complexes acidify benzylic protons upon π-coordination to the phenyl ring of substrates, facilitating deprotonation by stabilizing the corresponding benzylic carbanion. Cation-complexes with group(I) metals also acidify benzylic C-H bonds. These approaches enable a significant expansion of the scope and diversity of alkylarenes with various electrophilic reagents. In this review, we discuss the development of benzylic functionalization through deprotonation of η-arene complexes of transition-metals and cation-π interactions with group(I) metals, as well as progress made in catalysis through reversible arene-metal interactions.
苄基C-H官能团化是一种从简单易得的烷基苯制备复杂芳香分子的重要工具。虽然涉及通过氢原子转移或氧化产生苄基自由基或阳离子的方法已得到充分证明，但它们通常需要氧化条件。相比之下，去质子化方法提供了一种互补的途径，通过去质子化产生的苄基碳负离子来转化苄基C-H键。亲电过渡金属配合物在与底物的苯环进行π配位时会使苄基质子酸化，通过稳定相应的苄基碳负离子促进去质子化。与第（I）族金属形成的阳离子配合物也会使苄基C-H键酸化。这些方法能够显著扩展使用各种亲电试剂的烷基芳烃的范围和多样性。在本综述中，我们讨论了通过过渡金属的η-芳烃配合物的去质子化以及与第（I）族金属的阳离子-π相互作用实现苄基官能团化的发展，以及通过可逆的芳烃-金属相互作用在催化方面取得的进展。
