An Electrochemical Approach to Amine Synthesis from Nitrogen

项目摘要/摘要 含氮官能团构成了与健康相关的小分子中最大的类别之一。 因此，开发构建碳-氮键的新方法仍然是至关重要的 化学合成领域的创新机会。哈伯-博施进程可以说是最重要的 合成催化过程，其中大气中的氮(N2)被铁催化剂还原为氨(NH3) 在高温和高压下。相比之下，自然界的氮气固定催化剂，固氮酶，在常温下工作 使用双金属活性中心的条件。因此，许多定义明确的配位络合物 旨在研究氮气还原中的关键成键步骤，目标是设计更有效的催化剂 氨和其他附加值化合物的合成。虽然在催化方面已经取得了一些成功 氮气硅基化得到三(三烷基硅基)胺，目前还没有类似的胺催化过程的例子。 氮气通过碳-氮键形成的合成。氮气直接转化的当前策略 胺需要多步合成具有有机亲电性的金属-氮络合物以及随后的 产品在苛刻条件下放行。为了绕过这些限制，拟议的研究采用了 促进自由基官能化质子耦合电子转移途径的茂金属催化剂 金属-氮气催化剂。在有机自由基生成的复兴的推动下，轻松获得丰富的 烯烃，并通过利用金属-氮气催化剂的互补反应模式， 可以合成二次芳香胺和芳香胺产品。研究计划概述了具体的方法， 将对金属-氮络合物与有机自由基和金属氮化物的反应提供基本的见解， 通常建议的氮气还原中间体，与烯烃。这些研究将为 从最丰富的来源实现药物相关官能团的催化合成 氮气-氮气。

Project Summary/Abstract Nitrogen-containing functionalities constitute one of the largest classes within health-relevant small molecules. Therefore, the development of new methods to construct carbon–nitrogen bonds remains paramount among opportunities for innovation in chemical synthesis. The Haber–Bosch process is arguably the most important synthetic catalytic process, wherein atmospheric nitrogen (N2) is reduced to ammonia (NH3) by an iron catalyst under high temperature and pressure. In contrast, nature’s N2 fixation catalysts, nitrogenases, operate at ambient conditions using a bimetallic active site. As such, many well-defined coordination complexes have been developed to study key bond-forming steps in N2 reduction, with the goal of designing more efficient catalysts for the synthesis of ammonia and other value-added compounds. While there has been some success in catalytic N2 silylation to give tris(trialkylsilyl)amines, there are no examples of the analogous catalytic process for amine synthesis through carbon–nitrogen bond-formation from N2. Current strategies for the direct conversion of N2 amines require multistep synthetic sequences of metal–N2 complexes with organic electrophiles and subsequent product release under harsh conditions. To circumvent these limitations, the proposed research employs metallocene-based catalysts to promote proton-coupled electron-transfer pathways for radical functionalization of metal–N2 catalysts. Enabled by a renaissance in organic radical generation, easy access to a suite of abundant olefins, and by exploiting complementary reactivity modes of metal–N2 catalysts, a diverse range of primary, secondary, and aryl amine products can be synthesized. The research plan outlines specific approaches that will deliver fundamental insights into reactions of metal–N2 complexes with organic radicals and metal nitrides, commonly proposed intermediates in N2 reduction, with alkenes. These studies will provide the foundation for the realization of a catalytic synthesis of medicinally relevant functional groups from the most abundant source of nitrogen—N2.