CAREER: Aerobic Hypervalent Iodine Chemistry as a Platform for Oxidase Catalysis

氧气(O2)是空气的主要成分，也是制造化学品的理想原料。它广泛存在(我们呼吸的空气中的一种成分)，强氧化性，并产生无毒的副产品(如水)。根本性的挑战阻碍了O2在合成化学中的广泛使用。能够更好地利用氧气的新策略对于开发可持续的合成方法至关重要。在这个项目中，鲍尔斯博士正在开发合成方法，利用氧气生成高价碘化合物，这是一种有用的化学氧化剂。从氧气中成功地制备高价碘化合物有助于实现更高的氧气利用率的目标。这个想法是O2，它通常不与碘苯反应生成这些高价碘试剂，但在牺牲醛和卤化钴催化剂的存在下这样做。提出了三个研究领域：提高对随后的有机应用的理解，创新试剂的路线和结构，将碘试剂与不同的镝催化剂以及金属有机骨架和纳米颗粒的使用结合起来，以影响C-H活化。这些反应对化学工业非常重要--从新型药物的先进制造到其他具有商业重要性的化学品。鲍尔斯博士还在创建新的项目，以扩大对科学、技术、工程和数学(STEM)学科的参与。例如，正在为社区大学课程开发开放获取的教育资源。此外，针对德克萨斯州历史悠久的黑人学院和大学(HBCU)的STEM教育外展计划正在形成，以增加传统上代表性不足的群体对STEM的参与。在化学系化学催化项目的资助下，德克萨斯A&M大学的鲍尔斯博士正在开发可持续地产生用于氧化催化的高价碘试剂的新方法。高价碘试剂是一类选择性的双电子氧化剂，已被证明参与了多种底物的官能化反应，包括羰基氧化、烯烃1，2-二官能化、氧化脱芳构化、醇和胺氧化以及基团转移化学。通过转移在醛自氧化化学中产生的活性中间体，O2还原可以直接耦合到高价碘化合物的合成。这些需氧生成的中间体在催化中的应用使高价碘试剂的广泛底物功能化与氧气还原耦合在一起。这些反应适用于先进的化学制造技术，因为它们比目前用于制药和商业化学品制造的技术更具潜力、更可持续、成本更低。鲍尔斯博士积极参与开发有助于扩大科学、技术、工程和数学(STEM)学科参与度的新项目。这些活动包括为社区大学课程开发新的开放获取的教育资源，以及开发针对德克萨斯州历史悠久的黑人学院和大学(HBCU)的STEM教育外展计划，旨在增加传统上代表性较低的群体对STEM教育的参与。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Oxygen (O2) is a major component of air and an ideal raw material to make chemicals. It is widely available (a component of the air we breathe), strongly oxidizing, and produces non-toxic byproducts (e.g., water). Fundamental challenges prevent widespread use of O2 in synthetic chemistry. New strategies that enable greater utilization of O2 are critical to developing sustainable synthetic methods. In this project, Dr. Powers is developing synthetic methods to use O2 to generate hypervalent iodine compounds, a class of useful chemical oxidants. The successful preparation of hypervalent iodine compounds from O2 helps achieve the goal of greater O2 utilization. The idea is that O2, which normally does not react with iodobenzene to make these hypervalent iodine reagents but does so in the presence of sacrificial aldehydes and a cobalt halide catalyst. Three research areas are proposed: improve understanding of the ensuing organic applications, innovate on routes and structures to the reagents, and couple the use of the iodine reagents with diverse dirhodium catalysts, as well as metal organic frameworks and nanoparticles, to effect C-H activations. These reactions are important to the chemical industry - ranging from the advanced manufacturing of new pharmaceuticals to other chemicals of commercial importance. Dr. Powers is also creating new programs to expand participation in science, technology, engineering, and mathematics (STEM) disciplines. For example, open-access educational resources for community college curricula are being developed. In addition, STEM education outreach programs to Historically Black Colleges and Universities (HBCUs) in Texas and are being formed to increase STEM participation by traditionally underrepresented groups. With funding from the Chemical Catalysis Program of the Chemistry Division, Dr. Powers of Texas A&M University is developing new methods to sustainably generate hypervalent iodine reagents for use in oxidation catalysis. Hypervalent iodine reagents are a class of selective two-electron oxidants that have been demonstrated to participate is a wide variety of substrate functionalization reactions including carbonyl oxidation, olefin 1,2-difunctionalization, oxidative dearomatization, alcohol and amine oxidation, as well as group-transfer chemistry. By diverting reactive intermediates generated during aldehyde autoxidation chemistry, O2 reduction can be directly coupled to the synthesis of hypervalent iodine compounds. Application of those aerobically generated intermediates in catalysis enables the broad substrate functionalization of hypervalent iodine reagents to be coupled to O2 reduction. These reactions are applicable to advanced chemical manufacturing techniques as they are more potential more sustainable and less expensive than current techniques used in pharmaceuticals and commercial chemical manufacturing. Dr. Powers is actively engaged in developing new programs that contribute to expanded participation in science, technology, engineering, and mathematics (STEM) disciplines. These activities, which involve developing new open-access educational resources for community college curricula and developing STEM education outreach programs to Historically Black Colleges and Universities (HBCUs) in Texas are directed at increasing participation in STEM education by traditionally underrepresented groups.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.