Mechanisms of Complex Carbocation Rearrangements

University Of California-Davis, Davis CA

Investigators

Abstract

In this project funded by the Chemical Structure, Dynamic & Mechanism B Program of the Division of Chemistry, Professor Dean J. Tantillo of the Department of Chemistry at the University of California-Davis will use modern computer modeling techniques, coupled with laboratory experiments, to uncover fundamental principles of chemical reactivity that govern mechanisms of formation of complex molecules. This research will uncover principles of reactivity and test their generality. The mechanistic models resulting from this work will be of utility to those working in the synthetic organic, biological, physical organic and chemical education fields. In addition to the fundamental importance of the chemistry uncovered through this research, the projects pursued will be used to train students (graduate and undergraduate, several from underrepresented groups) in multidisciplinary approaches to mechanistic chemistry and expose them to careers that employ such techniques. In addition, new methods for making applied computational chemistry accessible to blind and visually impaired students will be developed as part of an effort to encourage this group to pursue careers in STEM fields. This research will advance knowledge in mechanistic chemistry through the construction of new mechanistic models for rearrangements of complex carbocations. Specific mechanistic models for particular terpene-forming carbocation rearrangements will be developed, and general principles of reactivity for carbocations with complex molecular architectures will be derived from extensive studies spanning different classes of carbocations. The goals of this research are to (a) use modern quantum chemical methods to assess the energetic viability of various carbocation cyclization and rearrangement mechanisms leading to terpene natural products, characterize the electronic structures of the intermediates and transition state structures involved in these processes, and assess the dynamical tendencies associated with the potential energy surfaces for these rearrangements, (b) assess the ability of these intermediates and transition state structures to engage in noncovalent/intermolecular interactions with functional groups present in enzyme active sites and assess the consequences of these interactions, and (c) uncover fundamental, general principles of carbocation reactivity in complex systems.