Research in my group is primarily aimed toward the development of catalysts and catalytic reactions and methods for organic synthesis. Ultimately, we are interested in using these methods to address problems in the synthesis of complex molecules possessing interesting structural, biological and physical properties. As such, our research program spans the areas of organic synthesis, catalysis, and organometallic chemistry.
Two mechanistically distinct applications of complexes with metal-ligand multiple bonds are illustrative of our approach. First, we envision a new approach to catalysis utilizing transition metal-ligand pi-bonds to activate sigma-bonds towards addition reactions. We are also examining metal-ligand and ancillary ligand combinations with the ultimate goal of developing enantioselective versions of these reactions. The concept of employing complexes containing metal-ligand multiple bonds as bifunctional catalysts for sigma-bond activation represents a dramatic shift from the traditional applications of metal-oxo complexes as catalysts for atom transfer (epoxidations, aziridinations and dihydroxylation) and for functional group oxidations. Second, we are developing metal-dioxo complexes as catalysts for three-component cycloadditions in which the oxo ligand is one of the partners. We are applying these cycloaddition reactions to the synthesis of natural products such as kallolide A (anti-inflammatory and cytotoxic properties).
A second area of research is the development of new catalysts and synthetic methods for the formation of carbon-carbon and carbon-heteroatom bonds. Of particular interest are addition reactions including additions to olefins and alkynes, alkene-alkene coupling and other atom transfer additions. For example, we are investigating catalytic methods for the addition of water and alcohols to enones as an alternative entry into aldol adducts. Our ultimate goal is to develop enantioselective variants of these reactions and utilize them in the synthesis of natural products such as epoxyquinol (antiangiogenic activity), the eudesmanolides (antitumor) and the amphidinolides (cytotoxic).
In the News
The problem is simple to understand. Molecules of carbon and other greenhouse gases absorb heat. The more greenhouse gases emitted into the atmosphere, the warmer the atmosphere becomes, exacerbating global climate change. Solving the problem is not so simple, especially with regards to aviation – the source of two-percent of the annual greenhouse gas emissions from human activity.
Infrared technique at Berkeley Lab’s Advanced Light Source could help improve flow reactor chemistry for pharmaceuticals and other products.
A long-abandoned fermentation process once used to turn starch into explosives can be used to produce renewable diesel fuel to replace the fossil fuels now used in transportation, UC Berkeley scientists have discovered.
Catalysts are substances that speed up the rates of chemical reactions without themselves being chemically changed. Industrial catalysts come in two main types – heterogeneous, in which the catalyst is in a different phase from the reactants; and homogeneous, in which catalyst and the reactants are in the same phase.