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.
