Research
Our group's research
Research in the Champagne group
Expanding and controlling the role of carbocation intermediates in organic synthesis
Carbocation reactivity is central to organic chemistry teaching and research. While the simplest cations are well-understood, there is still plenty to learn about their formation, rearrangements, and nucleophilic capture. This is especially true for non-classical (or bridged) cations, which have the additional exciting property of reacting stereospecifically. Our work in this field is multi-disciplinary, synthesizing probes of cation behavior to study their reactivity, and employing computational techniques such as Density Functional Theory (DFT) calculations and molecular dynamics to study carbocations and their reactions.
Studying reactive sulfur species in organic reactions and in biochemical pathways
Reactive sulfur species include hydrogen sulfide (H2S), persulfides (RSSH), and longer polysulfides, species that are intermediates in a plethora of organic transformations. These structures also have crucial signaling and antioxidant properties in mammalian biology, making them exciting targets of study. However, reactive sulfur species interconvert quickly in solution due to their thermodynamic and kinetic instability, making experimental analysis of those fleeting intermediates difficult. We employ DFT calculations to probe the chemical reactivity of reactive sulfur species in both organic and biological systems, use our results to predict approaches to control that reactivity, then test our predictions experimentally. We also synthesize photo- or nucleophile-triggered donors of reactive sulfur species and use those to ask key questions about their biological roles.
Computational investigations of organocatalyzed transformations
DFT calculations are now a widely-used tool to study mechanisms of organic reactions, as they allow investigations of transition structures at a reasonable computational cost. We use DFT calculations to study the origins of selectivity in chiral organocatalyzed reactions, so that we can fully understand their mechanisms and develop models of selectivity. Ion-pairing catalysis (also called phase-transfer catalysis) is our focus, for it is a method of choice for industrial asymmetric synthesis, yet the roles of the catalysts in the enantioselectivity are poorly understood. These computational studies will allow us to design better catalysts for industrially-important transformations.
Funding
We are grateful for the following agencies for funding our research over the years.
National Science Foundation (NSF)
CAREER: Advancing the Chemical Understanding of Reactive Sulfur Species Through Photoactivated Donors and Computational Tools (CHE-2441800, 2025-2030)
American Chemical Society (ACS) Petroleum Research Fund (PRF)
Probing the Generation, Rearrangements, and Capture of Carbocations through Ab Initio Molecular Dynamics Simulations (68837-ND4, 2025-2027)
Elemental Sulfur in Organic Chemistry: Computational and Experimental Investigations of Organic Polysulfide Intermediates (61891-DNI4, 2021-2023)
Advanced Cyberinfrastructure Coordination Ecosystem: Services & Support (ACCESS), previously Xtreme Science and Engineering Discovery Environment (XSEDE)
ACCESS is an advanced computing and data resource program supported by the U.S. National Science Foundation (NSF)
CHE240105 (Explore)
TG-CHE190061
TG-CHE200081