Mechanistic Studies of Halenium-Alkene Additions for Chemical Catalysis

该奖项由化学学部化学催化项目资助，资助对象为密歇根州立大学Babak Borhan教授，该项目旨在对不对称卤代官能化进行机理分析和发现。通过探索这些过程的机制细微差别，本研究将加速设计和发现新的卤化反应，改进催化剂，以及复杂结构的有效途径。该项目的有机合成、光谱技术、同位素分析和量子化学模型的跨学科结合为博士生提供了在分析、有机和物理化学界面进行培训的绝佳机会。与不同背景的pi一起工作，进行研究的化学研究生、本科生和暑期高中学生除了必须掌握的多种实验室技术外，还学习了批判性思维和沟通技巧。Borhan教授发现，有机催化剂（DHQD）2PHAL促进卤素向烯烃和相关底物的手性传递，为类似于最近的不对称环氧化、二羟基化和氢化反应的一般性和实用性打开了大门，这些反应是有机合成的里程碑式工具。这些新型的立体控制卤化反应可以快速获得具有生物和药物重要性的复杂结构。机械研究采用动力学分析；溶剂效应调查；同位素标记既可以追踪立体化学，又可以通过动力学同位素效应确定关键的速率和产物决定步骤；电子可调衬底和卤化剂的设计和合成；多核和多维核磁共振技术探测分子相互作用；以及详细的量子化学模拟来指导和解释实验。分子建模和机械探索也受益于James Jackson教授的参与，他是一位在计算、催化和绿色化学领域拥有丰富经验的物理有机化学家，他是该基金的共同负责人。

This award, funded by the Chemistry Division Chemical Catalysis program in the Division of Chemistry to Professor Babak Borhan at Michigan State University, enables mechanistic analysis and discovery of asymmetric halofunctionalizations. By probing the mechanistic nuances of these processes, this research will expedite design and discovery of new halogenation reactions, improved catalysts, and efficient routes to complex structures. The project's interdisciplinary combination of organic syntheses, spectroscopic techniques, isotopic analyses, and quantum chemical models offers an excellent opportunity for doctoral students to be trained at the interface of analytical, organic, and physical chemistry. Working with PIs of very different backgrounds, the chemistry graduate, undergraduate (UG), and summer high school (HS) students who perform the research learn critical thinking and communications skills, besides the multiple lab techniques they must master.Professor Borhan's discovery that organocatalyst (DHQD)2PHAL promotes chiral delivery of halogens to alkenes and related substrates opens the door to reactions analogous in generality and utility to recent asymmetric epoxidations, dihydroxylations, and hydrogenations, landmark tools of organic synthesis. These novel stereocontrolled halocyclizations give rapid access to complex structures of biological and pharmaceutical importance. Mechanistic studies employ kinetic analyses; solvent effect surveys; isotopic labeling both to trace stereochemistry and to identify key rate- and product-determining steps via kinetic isotope effects; design and synthesis of electronically adjustable substrates and halogenating agents; multinuclear and multidimensional NMR techniques to probe molecular interactions; and detailed quantum chemical simulations to guide and interpret experiments. Molecular modeling and mechanistic explorations also benefit from the involvement of Professor James Jackson, a physical organic chemist with substantial experience in computational, catalytic, and green chemistry areas, who serves as a Co-PI on this grant.