Research in the Schomaker group is driven by the need for more efficient methods to transform simple hydrocarbons into more complex building blocks for synthesis. Our program will encompass new catalyst development and optimization, elucidation of reaction mechanisms and applications of new methodologies to the synthesis of natural products and other useful molecules. Particular emphasis will be placed on the design of catalysts that can utilize inexpensive greenhouse gases for useful organic transformations. The potential applications of our new catalysts to industrially important transformations will also be explored. Projects in our group are designed to offer students the ability to gain skills that will serve them well throughout their scientific careers, whether in an academic, government or industrial setting. These include standard techniques for the synthesis of organic and organometallic compounds, the handling and manipulation of air-sensitive materials, mechanistic and kinetic studies, advanced NMR techniques, basic computational chemistry, total synthesis and training in scientific writing and presentation skills.
Multi-Component Reactions for the Formation of Multiple Carbon-Heteroatom Bonds
The oxidation of alkenes is a common method for the introduction of vicinal heteroatoms into unsaturated substrates. Much work has been devoted to olefin dihydroxylation, epoxidation, aziridination and aminohydroxylation, and more recently, diamination. However, many biologically active molecules contain multiple carbon-heteroatom bonds at contiguous carbons that currently require several steps to synthesize. We are interested in the development of well-defined methods to install three or more carbon-heteroatom bonds into an unsaturated step in a single pot. In particular, cumulenes have proven to be fruitful substrates in our initial studies. For example, the aziridination of allenes to strained bicyclic methylene aziridines yields a flexible scaffold that can be transformed to many valuable synthetic motifs containing various combinations of three or more carbon-heteroatom bonds. The types of reactivity that can be envisioned for these scaffolds provide many exciting opportunities for both methodology development and applications to total synthesis.
New Metal Complexes for the Activation of Nitrous Oxide and Carbon Dioxide
CO2 and N2O are potent greenhouse gases that are inexpensive, relatively non-toxic, non-flammable, can exhibit high atom economy and release environmentally benign by-products. However, the kinetic and thermodynamic stabilities of isolectronic CO2 and N2O represent a challenge for organometallic chemists, particularly in the activation of the latter. Our group has initiated a program to discover and design new modes of incorporating CO2 and N2O selectively into organic molecules, beginning with simple unsaturated substrates and progressing to renewable biomass feedstocks, including polyunsaturated fatty acids, carbohydrates and lignins. These studies will reveal new mechanistic avenues for the activation of CO2 while providing routes to high-value starting materials used in the pharmaceutical, polymer, agricultural and electronic markets. Three areas of current interest are oxidative carboxylation reactions that utilize N2O as the oxidant, methods for the conversion of olefins directly to acrylic acids using CO2 as the carboxylate source and the development of new methods for asymmetric carboxylation.
Synthesis and Use of Unusually Strained Rings for Activity-Based Protein Profiling
Polyamines are important components of many pharmaceuticals and biologically active molecules. They can be utilized as probes for the study of disease pathways, function as small molecule RNA inhibitors or act as chelates for metals in biomedical applications. We have developed new approaches to the synthesis of unusually strained 1,4-diazaspiro[2.2]pentane (DASP) ring systems that we are currently exploring as systems for activity-based protein profiling. The multident nature of DASPs may allow for discrimination amongst amino acids triads that are in different protein microenvironments, an attractive feature for applications in proteomics.
Total Synthesis of Natural Products
The total synthesis of natural products offers students a chance to develop strategic and tactical expertise in the construction of complex molecules, skills that will serve them well throughout their entire scientific careers. Obviously, interesting molecular architectures and the ability to stimulate new reaction development and highlight existing reaction methodologies are valid reasons for choosing a target. In addition, total synthesis of natural products that possess specific or unusual bioactivity can provide material for collaborative projects aimed at studying the mechanism of action of these molecules and lead to the development of more effective analogues.