With this award, the Chemical Synthesis Program of the NSF Division of Chemistry is supporting the research of Professor Seann Mulcahy. Professor Mulcahy is a faculty member in the Department of Chemistry and Biochemistry at Providence College, a primarily undergraduate liberal arts college in Providence, Rhode Island. Together with a team of undergraduate students, Professor Mulcahy is developing new chemical tools for making organic molecules known as atropisomers. These molecules are unique because they cannot fully rotate around one of their carbon-carbon single bonds. This limitation locks the atropisomers in two distinct propeller-like forms that are non-identical mirror images of one another. Preparing one or the other of these forms is a challenge in the field of chemical synthesis but access to these distinct molecules is important for pharmaceutical and material applications. Professor Mulcahy is researching ways to selectively make new atropisomers using a transition metal catalyst to stitch together the key components. A diverse team of undergraduate students are receiving training by working to optimize this catalytic reaction and study the properties of these molecules. Computational studies both at Providence College and in collaboration with Professor Jeffrey Gustafson at San Diego State University are being used to help guide these investigations. Professor Mulcahy is also organizing workshops in chemical synthesis for underrepresented high school students in the greater Providence region, creating a summer immersion program for high school juniors interested in research, and developing new resources for college students to cope with failure and be more resilient in STEM.
Transition metal catalysis is a powerful method for the construction of asymmetric carbon stereocenters; however, the use of transition metal catalysis to install other types of chirality is less well-developed. The Mulcahy group at Providence College is developing catalytic asymmetric methods to synthesize atropisomeric heterocyclic 1-aryl-beta-carbolines. The goal of this project is to develop a cationic rhodium(I)-catalyzed [2+2+2] cycloaddition strategy for the selective formation of one of the two mirror-image atropisomers using a combination of catalyst optimization, substrate engineering, and computational methods. The effects of chiral bidentate phosphine ligands and the substitution patterns of the reagents are being explored as key determinants of atroposelectivity. In addition, computational and physicochemical studies are being performed to determine the absolute configuration and establish the rates of racemization of the atropisomeric beta-carbolines. These activities are also serving as a platform for the education and training of a diverse set of undergraduate students in synthetic chemistry, as well as the recruitment and retention of students from underrepresented groups. The creation of new video resources to help students manage challenges that they might encounter in a research setting are being developed as a new resource to further support inclusion and expansion in STEM fields.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
