Development of and Mechanistic Studies on the Palladium and Iron-Cocatalyzed Nucleoboration of Olefins

钯铁共催化烯烃核硼化反应进展及机理研究

• 批准号: 2155133
• 负责人: Kami Hull
• 金额: $ 50万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2155133&HistoricalAwards=false
• 关键词: Development; Mechanistic; Studies; Palladium; Iron

With the support of the Chemical Catalysis Program in the Division of Chemistry, Kami L. Hull of the University of Texas at Austin (UT-Austin) is studying a palladium- and iron-catalyzed process that converts simple chemical feedstocks (olefins) into value-added products. This so-called "nucleoboration" method results in the addition of an atom of boron and one of another element, typically nitrogen, to the olefin in a finely controlled manner. Selective transformations exist to subsequently convert the boron atom into a wide variety of other substituents and the overall process promises to be a versatile approach for the manufacture of complex compounds and advanced materials of value to society. In combination with method development, the funded research encompasses detailed mechanistic studies designed to elucidate how the catalyst pair functions with the goals of advancing fundamental knowledge of transition metal-based catalysis and improving the efficiency and sustainability of chemical synthesis. The broader impacts of the funded project extend to the benefits accrued to society as Dr. Hull and her coworkers engage in an extensive range of educational and outreach activities, including: the ChemBridge program to improve the college readiness of young Texans who belong to groups underserved in STEM (science, technology, engineering and mathematics) fields, and ongoing efforts to propagate shared values of diversity, equity, and inclusivity among the faculty and students of UT-Austin.The funded research focuses on investigations of a recently discovered Pd/Fe-cocatalyzed aminoboration of alkenes and it features further development of the process (e.g., to expand both the substrate and nucleophile scope) and associated mechanistic studies to gain insights for the underlying role of the iron(II) triflate cocatalyst. Specifically, during the course of methodological development (Aim 1), reaction conditions for the successful aminoboration of norbornene [key reagents: PhthNH, B2Pin2, cat. Pd(MeCN)2Cl2, cat. Fe(OTf)2, and O2] will be further explored and extended to more challenging olefin substrates for which beta-hydride elimination following the Markovnikov addition stage of the process could be encountered. Nucleophiles other than N-based systems, such as O-based (e.g., phenols), S-based (e.g., thiols), and C-based (e.g., indoles), will also be investigated as will alternative transmetalation reagents (e.g., Si- and Sn-based) to potentially arrive upon a highly generalized nucleometallation process. In further efforts to broaden the versatility of the platform yet further, a remote nucleoboration transformation that incorporates a 'Pd-walking' stage (i.e., regioisomerization) prior to transmetalation is also being pursued. In mechanistic studies (Aim 2), the origin of the critical role for iron species in the transmetalation step of aminoboration is being explored as is its equally curious beneficial effect on the aza-Wacker process. Finally, in an effort to develop a more sustainable variant of the nucleoboration process (Aim 3), a heterogenous and recyclable Pd/Fe catalyst system is under development. All told, the studies being pursued are anticipated to extend the versatility of olefin difunctionalization chemistry and in so doing, facilitate the synthesis of important classes of nitrogen (and other heteroatom) containing compounds that are prominent among active pharmaceutical ingredients and other kinds of complex molecules of utility in science, engineering, and medicine.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在化学催化计划的支持下，德克萨斯大学奥斯汀分校（UT-AUSTIN）的Kami L. Hull正在研究钯和铁催化的过程，该过程将简单的化学原料（Olefins）转化为增值产品。这种所谓的“核化方法”方法导致硼原子的添加，而另一个元素（通常是氮，通常是氮）以精细控制的方式添加到烯烃中。有选择性转化，随后将硼原子转化为多种取代基，整个过程有望成为制造复杂化合物和对社会有价值的高级材料的多功能方法。结合方法开发，资助的研究涵盖了详细的机械研究，旨在阐明催化剂对如何发挥基本知识的基本知识，并提高化学合成的效率和可持续性。 The broader impacts of the funded project extend to the benefits accrued to society as Dr. Hull and her coworkers engage in an extensive range of educational and outreach activities, including: the ChemBridge program to improve the college readiness of young Texans who belong to groups underserved in STEM (science, technology, engineering and mathematics) fields, and ongoing efforts to propagate shared values of diversity, equity, and inclusivity among the faculty and students of该资助的研究重点是对最近发现的PD/Fe-核催化的烯烃的研究，并具有进一步的发展（例如，扩大底物和亲核范围）和相关的机械研究，以获得铁（II）Triflate CocaTalate CocaTalys的潜在作用。具体而言，在方法论发展过程中（AIM 1），成功的杂烯氨基酸的反应条件[关键试剂：phthnh，b2pin2，cat。 PD（MECN）2Cl2，CAT。 Fe（OTF）2和O2]将进一步探索并扩展到更具挑战性的烯烃底物，在该过程的Markovnikov加法阶段之后，可以遇到β-氢化物的消除。除基于N的系统以外的其他系统以外的其他系统（例如基于O的（例如苯酚），基于S的（例如硫醇）和基于C的基于C（例如吲哚）），也将随着替代性跨金属试剂（例如SII-和SN基于SI-和SN）的可能性来进行高度普遍的核量表分组过程。为了进一步拓宽平台的多功能性，在跨金属进行跨金属之前，还结合了“ PD步行”阶段（即区域异构化）的远程核化转换。在机械研究（AIM 2）中，正在探索铁物种在氨氧化体步骤中的关键作用的起源，以及其对Aza-Wacker工艺的同样奇怪的有益作用，也正在探索AMINOBOROTIAL。最后，为了开发核能过程中更可持续的变体（AIM 3），正在开发异质和可回收的PD/FE催化剂系统。总的来说，预计所进行的研究将扩大烯烃的多功能性化学的多功能性，并在这样做时促进氮（和其他杂原子）的重要类别的合成，这些化合物含有重要的化合物，这些化合物在活跃的药物成分和其他种类的复杂分子中均在科学上，并享有医学奖，并逐渐形成了nissf evern.the and Thersf and TheSf的复杂分子。通过基金会的智力优点和更广泛的影响评估标准通过评估来支持。