New Electron-Transfer Concepts in Organic Synthesis

Abstract: The Nacsa Group uses electron transfer techniques to address challenges in organic synthesis. Our lab works in two main areas. The first uses electrochemistry to develop new approaches for dehydration reactions, such as the synthesis of amides and esters from carboxylic acids, with an emphasis on catalysis. Dehydrative transformations are workhorse operations in pharmaceutical R&D, but owing to the wasteful reagents overwhelmingly used to accomplish them, industry has long called for methods that avoid these reagents.

Organic Syntheses Lecture: Synthetic Strategies via Photoreductive Activation of Energy Demanding Bonds

Abstract: The reductive activation of organic molecules through single electron transfer (SET) is routinely deployed in diverse synthetic settings. Conventional single-electron reductants, such as samarium diiodide (SmI2) or dissolving metals, are predominantly deployed (super)stoichiometrically. Within the context of catalytic approaches enabling the controlled one-electron reduction of common functional groups or inert bonds, photoredox catalysis provides an intuitive strategy to generate potent SET reductants that can activate challenging substrates.

Studies of Voltage-gated Sodium Channels & Bioelectricity: Opportunities and Challenges for Chemistry

Abstract: The Du Bois lab is interested in the molecular physiology of sodium channels in electrogenesis and nociception, work that may ultimately inform the development of new analgesic medicines. Our studies rely on molecular biology and electrophysiology to measure ionic currents in cells and capitalize on the availability of potent neurotoxins and derivatives thereof as selective reagents for manipulating channel function.

Organic Reactions Lecture: Synthesis of securines, secuarmines, and chartellines

Abstract: Securines and securamines are alkaloids that contain a cis-enamide, neopentylic alkyl chloride, bromoimidazole, and a pyrroloindoline that was reported to exist in a solvent-dependent equilibrium with the corresponding indole–macrolactam isomer. More complex isolates contain an oxidized hexacyclic structure, and varied bromination of the indoline that correlates with their cytotoxicity. We recently developed a flexible route that provides access to the three skeletally-distinct classes of isolates and which will support elucidation of their structure–function re

Overman Lecture: Chemical Synthesis of Antibiotics

Abstract: My research focuses on the use of component based convergent chemical synthesis for the discovery and manufacture of new antibiotics effective against multi-drug resistant modern bacterial pathogens. Many antibiotics approved for the treatment of human infectious diseases are natural products or are derived from them.

New Strategies to Prevent Premature Birth and Break Strong Bonds

Carbohydrates are the most abundant organic molecules on earth and are critical to a myriad of biological processes. The Vanderbilt Laboratory for Glycoscience uses a blend of synthetic organic chemistry and microbiology to elucidate the biological roles of carbohydrates, with a foci on advances in chemical synthesis and learning new mechanistic concepts. Emerging areas in the lab focus on the synthesis and evaluation of complex alkaloids. Our discussion will be divided into two categories: application of the host defense properties of human milk and the synthesis of iboga alkaloids.

Organic Syntheses Lecture: Synthesis Through C–C Bond Scission

Abstract: The topic of this talk is the radical chemistry based on C–C bond scission. The presentation will begin with another area of research endeavors in my group—phosphorus organocatalysis. It then will present how our need to create chiral phosphines, CarvoPhos, of particular configuration inspired our invention of a series of new reactions based on C–C bond cleavage. To be specific, we have implemented one-pot processes to ozonize alkenes into α-methoxyhydroperoxides, for subsequent Fe(II)-mediated reductive fragmentations that yield alkyl radical intermediates.

Post-translational modification proteomics in 4D

Spatial organization and temporal dynamics are essential properties of cellular signaling. Post-translational modifications (PTMs) to proteins relay biological signals by exerting precise spatiotemporal control over protein function, localization, and lifetime. A systems-level experimental map of post-translationally modified proteins across subcellular space and time would transform our understanding of how PTMs orchestrate complex cellular functions in response to biological stimuli. However, such a map is inaccessible with current technologies.

Strain-Release Pentafluorosulfanylation: Strange Molecules Doing Stranger Things

This presentation details recent progress in our laboratory toward the synthesis and evaluation of historically underemployed fluorinated functional groups that have been made more accessible using the TCICA/KF approach to oxidative fluorination. A major theme will be our recent merging of SF5 radical chemistry with strain-release functionalization of [1.1.1]propellane and [1.1.0]bicyclobutanes. Structural consequences of making these SF5-based "hybrid isosteres" and preliminary mechanistic insight will be discussed.

Organic Reactions Lecture: Radical isomerization tools outside the confines of thermodynamics

Abstract: Selective isomerization reactions are valuable tools for the positional and spatial interconversion of functional groups. Catalytic isomerizations are frequently governed by thermodynamic control, enabling predictable access to product distributions defined by the stability of starting and product isomers, but limiting opportunities for tunable control.

UCI Department of Chemistry

Organic Seminar