Biocatalytic C–H Functionalization Forms Nitrogen Heterocycles

项目概要和摘要 氮杂环化合物是普遍存在的药效团，在近60%的药物中发现。尽管 这些部分的普遍性是，没有催化剂类别形成C-N键对映选择性地产生 不同的含氮杂环（即环胺和内酰胺）。 因此，开发用于直接和方便地获得氮杂环的催化剂具有重要的合成和应用价值。 医学兴趣氮杂环化合物合成的理想方法是分子内氮烯插入法 反应形成新的C-N键。Breslow，Du Bois，Betley和Zhang的实验室已经奠定了 为发展这些氮烯插入反应奠定了基础。但是，目前的贵金属催化剂 是有限的，并且显示很少或没有对映选择性。工程酶催化剂可以解决这个长期存在的问题。 合成挑战，因为它们在温和条件下具有精确的区域选择性、化学选择性和立体选择性， 动力学和生物合成的可再生材料。工程血红素蛋白的研究进展 表明它们催化类卡宾和类硝戊环的不对称反应的数目不断增加。 我建议设计血红素蛋白，通过氮烯插入反应催化C-N键的形成， 形成重要的含氮杂环（即环胺和内酰胺）。这种反应是未知的 在自然界和授予现成的访问许多生物活性分子。具体目标是：（1）发展 用于氮烯C-H插入反应形成环胺的血红素蛋白;（2）开发用于氮烯的血红素蛋白 C-H插入反应形成内酰胺;（3）合理化开发血红素蛋白的选择性起源， 设计新的反应性我将开始筛选汇编板包含数百阿诺德 实验室的血红素蛋白，催化各种卡宾和氮烯转移和插入反应，对五个 安全易合成的氮烯来源。这个过程将确定一个酶氮烯源对优化 定向进化。经过多轮进化，我将分析生物催化剂的进化 轨迹与计算模型，以指导未来的进化运动，并简化选择突变 进化酶催化新自然反应的位点。总体而言， 这样的生物催化剂将允许高价值商品化学品的可持续和不对称合成， 药效团、天然产物和药物。

PROJECT SUMMARY & ABSTRACT Nitrogen heterocycles are ubiquitous pharmacophores found in nearly 60% of all pharmaceuticals. Despite the prevalence of these moieties there are no catalyst classes that form C–N bonds enantioselectively to produce diverse nitrogen-containing heterocycles (i.e. cyclic amines and lactams) in an industrially viable fashion. Therefore, developing catalysts for direct and expedient access to nitrogen heterocycles is of great synthetic and medicinal interest. A desirable method for nitrogen heterocycle synthesis is using intramolecular nitrene insertion reactions to form a new C–N bond. The laboratories of Breslow, Du Bois, Betley, and Zhang have laid the instrumental groundwork for developing these nitrene insertion reactions. But, current precious metal catalysts are limited and display little to no enantioselectivity. Engineered enzyme catalysts can solve this longstanding synthetic challenge as they have exquisite regio-, chemo-, and stereo-selectivity in mild conditions with fast kinetics and are biosynthesized from renewable materials. Ongoing research on engineered hemoproteins shows that they catalyze an ever increasing number of asymmetric reactions of carbenoids and nitrenoids. I propose to engineer hemoproteins to catalyze C–N bond formation by nitrene insertion reactions to directly form important nitrogen-containing heterocycles (i.e. cyclic amines and lactams). Such reactions are unknown in Nature and grant ready access to numerous bioactive molecules. The specific aims are: (1) to develop hemoproteins for nitrene C–H insertion reactions to form cyclic amines; (2) to develop hemoproteins for nitrene C–H insertion reactions to form lactams; (3) rationalize the origins of selectivity in developed hemoproteins for engineering new reactivity. I will begin by screening compilation plates containing hundreds of the Arnold laboratory’s hemoproteins that catalyze various carbene and nitrene transfer and insertion reactions against five safe and easy-to-synthesize nitrene sources. This process will identify an enzyme-nitrene-source pair to optimize with directed evolution. After multiple rounds of evolution, I will then analyze the biocatalyst evolutionary trajectory with computational models to guide future evolutionary campaigns and streamline choosing mutational sites for evolving enzymes to catalyze new-to-Nature reactions. In total, development and implementation of such biocatalysts will allow for sustainable and asymmetric syntheses of highly valuable commodity chemicals, pharmacophores, natural products and pharmaceuticals.