Photoinduced Nickel-Catalyzed Selective N-Demethylation of Trialkylamines Using C(sp2)–Bromides as HAT Reagents,Journal of the American Chemical Society

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Photoinduced Nickel-Catalyzed Selective N-Demethylation of Trialkylamines Using C(sp2)–Bromides as HAT Reagents
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2023-02-01 , DOI: 10.1021/jacs.2c12767
Xiao Zhang ₁ , Yangyang Shen ₁ , Tomislav Rovis ₁

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N-Demethylation of trialkylamines is a useful transformation, but typically requires harsh reaction conditions and stepwise procedures, as well as judicious protection of labile functional groups. Herein we report a mild, catalytic approach for the demethylation of trialkylamines by utilizing photoinduced nickel catalysis wherein C(sp²)–bromides serve as hydrogen-atom transfer (HAT) reagents. This method achieves direct demethylation of trialkylamines with wide functional group compatibility, making it highly suitable for late-stage derivatization of complex molecules. Mechanistic investigations provide evidence that C(sp²) radicals generated via photoinduced Ni–C(sp²) bond homolysis are involved in hydrogen atom abstraction from trialkylamines. Utilizing steric control of the C(sp²)–bromides, our HAT approach achieves demethylation with excellent site selectivity in the presence of benzyl-substituted amines, which is complementary to the selectivity of classical approaches that afford debenzylation product instead.

中文翻译：

使用 C(sp2)–溴化物作为 HAT 试剂的光诱导镍催化三烷基胺的选择性 N-脱甲基化

三烷基胺的N-去甲基化是一种有用的转化，但通常需要苛刻的反应条件和逐步程序，以及对不稳定官能团的明智保护。在此，我们报告了一种利用光诱导镍催化进行三烷基胺去甲基化的温和催化方法，其中 C(sp ² )-溴化物充当氢原子转移 (HAT) 试剂。该方法实现了三烷基胺的直接去甲基化，具有广泛的官能团兼容性，非常适合复杂分子的后期衍生化。机理研究提供的证据表明，通过光诱导的 Ni-C(sp ² ) 键均裂产生的 C(sp ² ) 自由基参与了从三烷基胺中夺取氢原子。利用 C(sp ² )–溴化物的空间控制，我们的 HAT 方法在苄基取代胺存在的情况下以优异的位点选择性实现了脱甲基化，这与提供脱苄基产物的经典方法的选择性相补充。

更新日期：2023-02-01

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