华中师范大学肖文精团队报道了用于苯基、丙基或烯基自由基不对称芳基化的通用铜盒体系。相关研究成果于2024年7月27日发表在国际知名学术期刊《德国应用化学》。

最近，涉及自由基的芳基交叉偶联反应已成为获得有价值的芳基取代基序的一种有吸引力的策略。然而，仍然存在一些挑战，例如自由基前体/受体的范围有限，缺乏通用的不对称催化体系，特别是在多组分变体方面。

该文中，研究人员报道了一种通用的铜盒体系，用于乙烯基芳烃和1,3-烯炔与肟碳酸酯和芳基硼酸的不对称三组分芳基交叉偶联。反应在可见光照射或不照射的实际条件下进行，得到具有良好对映选择性的手性1,1-二芳基烷烃、苄基炔烃和二烯烃。

机理研究表明，铜/Box配合物在自由基生成和随后的不对称交叉偶联中起着双重作用。在1,3-烯炔的情况下，可见光照射可以提高铜/Box复合物对初始自由基生成的活性，使自由基形成和交叉偶联之间的效率更好地匹配。

附：英文原文

Title: A General Copper-Box System for the Asymmetric Arylative Functionalization of Benzylic, Propargylic or Allenylic Radicals

Author: Peng-Zi Wang, Zhihan Zhang, Min Jiang, Jia-Rong Chen, Wen-Jing Xiao

Issue&Volume: 2024-07-27

Abstract: Radical-involved arylative cross-coupling reactions have recently emerged as an attractive strategy to access valuable aryl-substituted motifs. However, there still exist several challenges such as limited scope of radical precursors/acceptors, and lack of general asymmetric catalytic systems, especially regarding the multicomponent variants. Herein, we reported a general copper-Box system for asymmetric three-component arylative radical cross-coupling of vinylarenes and 1,3-enynes, with oxime carbonates and aryl boronic acids. The reactions proceed under practical conditions in the absence or presence of visible-light irradiation, affording chiral 1,1-diarylalkanes, benzylic alkynes and allenes with good enantioselectivities. Mechanistic studies imply that the copper/Box complexes play a dual role in both radical generation and ensuing asymmetric cross-coupling. In the cases of 1,3-enynes, visible-light irradiation could improve the activity of copper/Box complex toward the initial radical generation, enabling better efficiency match between radical formation and cross-coupling.

DOI: 10.1002/anie.202411469

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202411469