Applications of Oxidatively Generated Carbocations in Organic Synthesis

氧化生成的碳正离子在有机合成中的应用

• 批准号: 2154551
• 负责人: Paul Floreancig
• 金额: $ 50.69万
• 依托单位: University of Pittsburgh
• 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: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2154551&HistoricalAwards=false
• 关键词: Applications; Oxidatively; Generated; Carbocations; Organic

With the support of the Chemical Synthesis (SYN) Program in the Division of Chemistry, Professor Paul Floreancig of the University of Pittsburgh is studying new methods to prepare value-added materials from simple precursors via oxidative transformations. The approaches being developed are based on carbon-hydrogen bond cleavage reactions and include the use of electricity as an energy source in combination with an electrocatalyst to generate synthetically useful positively charged intermediates called carbocations. The pathways by which these intermediates emerge are being studied in detail and their inherent reactivity will be exploited to produce structurally complex molecules that are of potential utility as pharmaceutical agents, agrochemicals, and other materials of value to science, engineering, and commerce. The broader impacts of the funded project extend to the benefits accrued to society as Professor Floreancig and his coworkers engage in a variety of educational and outreach activities in the greater Pittsburgh area. In a signature effort designed to support future leaders in the chemical sciences, Professor Floreancig will lead workshops to prepare senior graduate students and post-doctoral associates at the University of Pittsburgh for possible transitions to independent careers as junior academics. Support for this project is also aiding Professor Floreancig's ongoing efforts to increase the diversity of the graduate student body at the University of Pittsburgh by the establishment of protocols designed to remove implicit biases during the graduate admissions process.The funded research is focused on fundamental mechanistic studies of oxidative carbon–hydrogen bond cleavage processes from allylic ethers and application of the insights gained to the design of new chemical reactions. A primary goal of the study is to understand the impact of remote functional groups on the kinetics of hydride-abstraction reactions with quinone (e.g., DDQ) and oxoammonium ion (e.g., Bobbitt's salt) oxidants. Understanding these effects will aid in the design of oxidative transformations that proceed at a sufficient rate to be applicable to an environmentally benign electrocatalytic protocol recently reported by the Floreancig group. Remote conformational effects impacting the oxidatively-generated oxocarbenium ions through electrostatic interactions will be investigated with the objective of enhancing stereocontrol in cationic cycloaddition reactions. Acyliminium ion formation will also be studied with the expectation of devising new oxidative processes for the synthesis of nitrogen-containing compounds. This objective is founded on understanding the conformational preferences of highly substituted acyliminium ions and exploiting the results for stereocontrolled heterocycle formation through rearrangement processes. Conformational preferences will also be used to instruct on the design of optimal substrates for stereoselective quaternary carbon formation with applications to complex alkaloid synthesis. The findings of the research are anticipated to provide the synthetic chemistry community with new transformations, valuable mechanistic insights, and blueprints for designing additional oxidative functionalization reactions going forward.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.

在化学综合（SYN）方案的支持下，匹兹堡大学的Paul Floreancig教授正在研究通过氧化转化从简单前体制备增值材料的新方法。 The approaches are developed are based on carbon-hydrogen bond cleavage reactions and include the use of electricity as an energy source in combination with an electrocatalyst to generate synthetically useful The pathways by which these intermediates emerge are being studied in detail and their inherit reactivity will be explored to produce structurally complex molecules that are of potential utility as pharmaceutical agents, agrochemicals, and other materials of value to science,工程和商业。该资金项目的更广泛的影响扩大到了弗洛伦西格教授和他的同事在大匹兹堡地区从事各种教育和外展活动，从而扩大了对社会的收益。在旨在支持化学科学领域的未来领导者的签名工作中，Floreancig教授将主持研讨会，为匹兹堡大学的高级研究生和博士后伙伴做好准备，以作为初级学者的独立职业过渡。 Support for this project is also aiding Professor Floreancig's ongoing efforts to increase the diversity of The graduate student body at the University of Pittsburgh by the establishment of protocols designed to remove implicit biases during the graduate admissions process.The funded research is focused on fundamental mechanistic studies of oxide carbon–hydrogen bond cleavage processes from allic ethers and application of the insights gained to the design of new chemical reactions.该研究的主要目的是了解远程官能团对与喹酮（例如DDQ）和oxoammonium离子（例如Bobbitt's Salt）氧化剂的氢化物抗反应动力学的影响。了解这些效果将有助于设计氧化转化，这些转化以足够的速度进行，适用于FloreAncig Group最近报道的环境良性电催化方案。将研究通过静电相互作用影响氧化产生的氧化核离子的远程构象作用，以增强阳离子环载反应中的立体控制。还将研究丙二烷离子的形成，期望为合成含氮的化合物的新氧化物过程。该目标建立在理解高度取代的酰基离子的会议偏好，并通过重排过程利用结果来实现立体控制的杂环形成。构象偏好还将用于指导设计最佳底物的立体选择性碳形成，并应用于复杂的生物碱合成。预计该研究的结果将为合成化学社区提供新的转变，有价值的机理见解和蓝图，用于设计额外的氧化功能化反应。该奖项反映了NSF的法定任务，并通过使用该基金会的知识分子和更广泛的影响来评估NSF的法定任务。