The Division of Chemistry supports Doris Pun of the University of Wisconsin - Madison as an American Competitiveness in Chemistry Fellow. Dr. Pun will develop catalysts and methods to selectively dehydrogenate partially-unsaturated ring systems using molecular oxygen as the oxidizing agent. She will collaborate with scientists at Eli Lilly to develop the methodology in a process-chemistry environment. For her plan for broadening participation, the PI will work with colleagues from SCIENCountErs (a collaborative program between the University and the Boys and Girls Clubs of Dane County) and the Expanding Your Horizons (EYH) Conference (a program for girls and their parents) to develop curriculum materials and hands-on activities for young people demonstrating green-chemistry principles.
Research like that of Dr. Pun is aimed at developing better routes for the synthesis of pure chemical compounds. These chemicals are used in consumer products as well as in pharmaceuticals. The particular methods that Dr. Pun is developing are "green" in that they use environmentally benign reagents (oxygen) and produce relatively benign waste. The hope is to develop more sustainable ways to produce the chemical compounds that society depends upon. The efforts at broadening participation being pursued by Dr. Pun will enable the development of a talented and diverse scientific workforce.
Objectives: Arenes, or cyclic molecules with C=C bonds (Scheme 1, right), are ubiquitious in chemistry, and are featured prominently in biologically active molecules and pharmaceuticals. Many of these molecules of interest are complex and the traditional synthetic methods include multi-step reactions of simple arenes. The objectives of this project were the complementary single-step hydrogen (H2) removal of substituted cyclic ring frameworks via "green" routes (Scheme 1). Broadening the participation of underrepresented groups in the sciences through a series of lesson plans and workshops focused on sustainability is another project objective. Intellectual Merit Activities: The project focuses on the development of a new, "green" aerobic palladium-catalyzed reaction towards the synthesis of complex arenes, such as a precursor drug to treat ovarian cancer (Scheme 2 right). We identified an efficient palladium catalyst system that show high yields for this specific transformation (Scheme 2) and explored the catalyst’s scope and utility to demonstrate high versatility. Through a series of mechanistic investigations, I have identified the active catalytic species to provide leads to superior catalytic methods for future industrial-scale implementation. In addition, I developed a complementary anaerobic synthetic methodology employing catalytic iridium. This latter method has demonstrated utility in the formation of several classes of pharmaceutically interesting arenes, such as an important precursor towards the synthesis of the anti-inflammatory drug candidate, Indoxam (Scheme 3). These two methodologies provide a range of methods to synthesize pharmaceutically relevant molecules effectively and efficiently. Broader Impacts: Partnering with the Institute of Chemical Education (ICE) at University of Wisconsin-Madison and the Expanding Your Horizons (EYH) program, I helped to inspire the next generation of scientists and engineers. A series of hands-on Green Chemistry lesson plans (10) were designed, developed, and implemented at two local Boys and Girls Clubs during the Spring 2011 semester (Jan. 25 – Apr. 20, 2011). Through these lessons, I demonstrated how chemists in academic and industrial settings are deeply conscientious of their environmental impact, with the ultimate anticipation that the K – 8th grade students, as future scientists and engineers, implement similar or improved practices. In particular, the students explored the 12 Principles of Green Chemistry, water purification techniques, recycling, composting, biomimicry, polymers and polymer recycling, catalysts and enzymes, and energy alternatives. Through participation at the annual EYH conferences, I also hosted and developed a total of 4 Chemistry workshops to encourage young women in the 6th – 12th grade to pursue careers in math, science, and engineering. Between both sets of activities, students learned a range of important scientific techniques, including developing hypotheses, designing experiments, and recording observations to draw conclusions.
