Biocatalytic C–H Functionalization Forms Nitrogen Heterocycles

项目总结与摘要 氮杂环是几乎60%的药物中普遍存在的药效团。尽管 这些部分的普遍存在没有催化剂类选择性地形成C-N键来产生 工业上可行的多种含氮杂环(即环胺和内酰胺)。 因此，开发直接和方便地获得氮杂环的催化剂具有重要的合成和 药用价值。一种合成氮杂环的理想方法是分子内插入氮化物。 反应形成新的碳-氮键。布雷斯洛、杜博伊斯、贝特利和张的实验室已经奠定了 开发这些氮化物插入反应的仪器基础。但是，目前的贵金属催化剂 都是有限的，几乎没有对映体选择性。工程酶催化剂可以解决这个由来已久的问题 合成挑战，因为它们在温和的条件下具有精致的区域、化学和立体选择性 Kinetics和由可再生材料生物合成。工程化血红素蛋白的研究进展 结果表明，它们催化了越来越多的类卡宾和类硝基的不对称反应。 我建议改造血红素蛋白，通过氮插入反应催化C-N键的形成，从而直接 形成重要的含氮杂环(即环胺和内酰胺)。这种反应是未知的。 在自然界中，并允许随时访问许多生物活性分子。具体目标是：(1)发展 用于氮化物C-H插入反应形成环胺的血球蛋白；(2)开发用于氮气的血球蛋白 C-H插入反应形成内酰胺类；(3)使已开发的血红蛋白的选择性来源合理化 设计新的反应性。我将从筛选包含数百本阿诺德的汇编模板开始 实验室中催化各种卡宾和硝烯转移和插入反应的血红蛋白 安全且易于合成的氮气源。这一过程将确定要优化的酶-氮-源对 通过定向进化。经过多轮进化后，我将分析生物催化剂的进化 使用计算模型指导未来的进化活动并简化选择突变的轨迹 进化酶的位置，以催化新的自然反应。总之，制定和实施 这种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、天然产品和药品。

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.