Experimental and Theoretical Investigations of Organic Reaction Rates and Mechanisms

This research project, led by Professor Kendall N. Houk of the University of California-Los Angeles and funded by the Chemical Mechanism, Function, and Properties Program in the Division of Chemistry, involves computer calculations using the methods of quantum mechanics and molecular dynamics to understand the factors that control chemical reactivity. Professor Houk and his team explore the detailed mechanisms by which reactions occur and predict how changing the conditions, substrates, and catalysts may improve the yields and selectivities of reaction. This research is often collaborative, where the team helps to explain the mechanisms and selectivities observed in experiments by collaborators. This project will train graduate students and postdoctoral fellows to become expert computational chemists and to collaborate with experimentalists, great preparation for careers in industry or academia. The specific projects involve exploration of how polar substituents influence the role of orbital symmetry on the control of rates and stereoselectivities of pericyclic reactions. They also study mechanisms of cycloadditions, electrocyclizations, and sigmatropic shifts with quasi-classical molecular dynamics to obtain time-resolved insights into mechanisms and to understand selectivity of ambimodal reactions involving post-transition state bifurcations. They are further developing quantitative reactivity predictions for electrophilic, nucleophilic, radical, and pericyclic reactions, including a new model that combines Evans-Polanyi factors and diradical character. In addition, new enzymes with novel activities are being predicted, to be tested by collaborating enzymologists. 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.