Presidential Young Investigator: Application of Group Transfer from Metals to Olefins

总统青年研究员：从金属到烯烃的基团转移的应用

• 批准号: 9057740
• 负责人: Eric Jacobsen
• 金额: $ 15万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-07-01 至 1993-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9057740&HistoricalAwards=false
• 关键词: Presidential; Young; Investigator; Application; Group

Dr. Eric N. Jacobsen is being funded by the Organic Synthesis Program as a Presidential Young Investigator. He will be studying the development of enantioselective catalysts for organic synthesis. The oxidation of unfunctionalized olefins will be the first reaction that he will explore. Facial selectivity in group transfer to a prochiral olefin can be controlled by purely non-bonded interactions or by constraining the degrees of freedom in diastereometric transition states through substrate pre-coordination. Catalytic systems are being developed based on both principles. A series of chiral manganese complexes have been designed which catalyze epoxidation of isolated and unfunctionalized olefins by iodosoarenes with up to 33% enantiomeric excess. The ligands for these complexes are readily prepared by condensation of chiral diamines with salicylaldehyde drivatives, permitting systematic variation of their steric and electronic properties. Current efforts are directed toward tuning the steric environment surrounding the reactive site in order to increase enantioselectivity to synthetically useful levels and to use observed stereochemical preferences to map out the trajectory of olefin approach to the intermediate metal oxo species. The results with six catalysts prepared to date and examination of a crystal structure of the most effective system have allowed a detailed transition structure for oxygen-atom-transfer from manganese to olefin to be developed. This model is now being refined by systematic variation of metal, ligand, and substrate; the elucidation of a transition structure which holds predictive value with regard to stereochemistry will also provide mechanistic insight into the general question of oxygen-atom transfer from metals to olefins, an important step in a wide range of laboratory, industrial, and biological processes.

Eric N. Jacobsen博士是由有机合成计划资助的，担任总统年轻调查员。 他将研究有机合成的对映选择性催化剂的开发。 未官能化的烯烃的氧化将是他将要探索的第一个反应。 小组转移到元素烯烃中的面部选择性可以通过纯粹的非键相互作用或通过底物预协调来控制映射过渡态中的自由度来控制。 催化系统都是基于这两种原理开发的。 已经设计了一系列的手性锰配合物，可催化碘碳烯烯类分离和未官能化的烯烃的环氧化，对照多体超过33％。 这些配合物的配体很容易通过与水杨醛驱动因素缩合，可以使其空间和电子特性的系统变化。 目前的努力是针对反应位点周围的空间环境的，以提高对合成有用水平的对映选择性，并使用观察到的立体化学偏好来绘制烯烃方法对中间金属氧气物种的轨迹。 六个催化剂的催化剂和最有效系统的晶体结构的结果允许开发氧气原子转移的详细过渡结构，从而开发了详细的过渡结构。 现在，该模型通过金属，配体和底物的系统变化来完善。对立体化学具有预测价值的过渡结构的阐明还将提供机械洞察力，以了解从金属转移到烯烃的一般问题，这是在广泛的实验室，工业，生物学过程中迈出的重要一步。