AbstractAromatic amines are ubiquitous moieties in organic molecules and their direct functionalization is of great interest in many research areas due to their prevalence in pharmaceuticals and organic electronics. While several synthetic tools exist for the ortho‐ and para‐functionalization of anilines, the functionalization of the less reactive meta‐position is not easy to achieve with current methods. To date, the meta‐C−H arylation of aniline derivatives has been restricted to either the use of directing groups & templates, or their transformation into anilides & quaternary anilinium salts. Herein, we report the first general and efficient meta‐C−H‐arylation of non‐directed aniline derivatives via cooperative catalysis with a palladium–S,O‐ligand–norbornene system. The reaction proceeds under mild conditions with a wide range of aniline derivatives and aryl iodides, while being operationally simple and scalable. Our preliminary mechanistic investigation–including the isolation of several palladium complexes and deuterium experiments–reveal useful insights into the substituent‐effects of both the aniline‐substrate and the norbornene‐mediator during the meta‐C−H activation step.
摘要 芳香胺是有机分子中无处不在的分子,由于芳香胺在医药和有机电子产品中的广泛应用,其直接官能化在许多研究领域都引起了极大的兴趣。虽然有多种合成工具可以实现苯胺的正官能化和对官能化,但目前的方法却难以实现反应性较低的元位的官能化。迄今为止,苯胺衍生物的元-C-H 芳基化仅限于使用定向基团和模板,或将其转化为苯胺类和季胺盐。在此,我们首次报道了通过钯-S,O-配体-降冰片烯体系的协同催化,对非定向苯胺衍生物进行通用而高效的元-C-H-芳基化反应。该反应在温和的条件下进行,适用于多种苯胺衍生物和芳基碘化物,同时操作简单、规模可控。我们的初步机理研究--包括分离几种钯配合物和氘实验--揭示了在元-C-H 活化步骤中苯胺底物和降冰片烯介质的取代效应。