Brandon Ashfeld

Brandon Ashfeld

Synthetic Organic Chemistry Transition Metal Catalysis in Synthetic Methods Development

Biography

2014-present
Associate Professor, University of Notre Dame
2007-2014
Assistant Professor, University of Notre Dame
2004-2007
Ruth L. Kirschstein NIH Postdoctoral Fellow, Stanford University
2004
Ph.D. in Chemistry, University of Texas at Austin
1998
B.S. in Chemistry, University of Minnesota-Twin Cities

Selected Awards

2011
NSF CAREER Award
2009
University of Notre Dame Faculty Scholarship Award

Research Interests

Our research program is focused on the development of new methods to enable unconventional bond formations in the synthesis of complex natural products and designed materials. Our main objective is to use new chemical constructs to design and synthesize improved chemotherapies for brain and CNS cancers, and materials that will ultimately lead to the reduction of atmospheric concentrations of anthropogenic CO2.
Designing Brain and CNS Cancer Chemotherapeutics.
We seek to addresses the issue of suitable brain and CNS drug treatment options by focusing on natural products with promising cytotoxicity that also display blood brain barrier (BBB) transcytosis properties. Specifically, the families of diarylheptanoids and glycosidic marine toxin natural products have captured our attention due to the potent anticancer activity exhibited by multiple members of each class. We are currently working toward the development of two new synthetic methods that will enable the efficient, and scalable construction of these natural products for the development of new CNS cancer chemotherapeutics. The first approach is based on the conceptual design of a tandem reaction sequence composed of mechanistically distinct transformations facilitated by a single catalyst to rapidly assemble all alkyl-substituted tertiary carbons centers. By exploiting aldehydes as traceless dielectrophilic entities, in conjunction with the bifunctional attributes of titanocene, we can construct multiple C–C and C–X bonds in a highly convergent fragment coupling. Our second area of methods development focuses on the formation of Csp2–N and Csp2–C bonds, which constitutes one of the most vibrant areas of research in synthetic organic chemistry today. Unfortunately, conventional multistep protocols involving organometallic reagents and transition metal complexes can complicate complex molecule synthesis. Our program is working toward providing a solution to this long-standing problem in organic synthesis through the development phosphorus-mediated C–C and C–N bond formations that ultimately circumvents the need for traditional organometallic or transition metal-based reagents.
 
Innovating the Chemistry of Covalent Carbon Capture.
Managing the impact of human activities on the concentration of CO2 in the atmosphere is the most far-reaching environmental challenge facing the world today. Carbon capture and separation is an integral part of our energy future, independent of its application to today’s coal-fired power plants. Our research program is working toward the development of a strategy to control atmospheric, anthropogenic CO2 concentrations through the design of energy efficient carbon capture and sequestration materials. Our ultimate goal is the development of a regenerative material that will undergo selective super-stoichiometric carbon capture with near-zero parasitic energy consumption. Recognizing that C–C and C–X chemical bonds are convenient media for energy storage, transport, and consumption, our efforts rely on the design and synthesis of functionalized N-heterocyclic anions and carbenes for energy efficient gas phase removal of CO2.
 

Recent Papers

  • Fleury, L. M.; Wilson, E. E.; Vogt, M.; Fan, T. J.; Oliver, A. G.; Ashfeld, B. L. “An Amine-Free Approach Toward N-Toluenesulfonyl Amidine Construction: A Phosphite-Mediated Beckmann-Like Ligation of Oximes and Azides.” Angew. Chem. Int. Ed. 2013, 52 (44), 11589-11593.
  • Vogt, M.; Bennett, J. E.; Huang, Y.; Wu, C.; Brennecke, J. F.; Schneider, W. F.; Ashfeld, B. L. "Solid State Covalent Capture of CO2 Using N-Heterocyclic Carbenes." Chem. Eur. J. 2013, 19 (34), 11134-11138.
  • Lepore, A. J.; Pinkerton, D. M.; Ashfeld, B. L. “Relay Redox and Lewis Acid Catalysis in the Titanocene-Catalyzed Multicomponent Assembly of 1,5-Enynes." Adv. Synth. Catal. 2013, 355, 1500-1504.
  • Campos, C. A.; Gianino, J. B.; Ashfeld, B. L. "Bifunctional Titanocene Catalysis in Multicomponent Couplings: A Convergent Assembly of β-Alkynyl Ketones." Org. Lett. 2013, 15 (11), 2656-2659. 
  • Gianino, J. B.; Ashfeld, B. L., "Titanocene-Catalyzed Multicomponent Coupling Approach To Diarylethynyl Methanes." J. Am. Chem. Soc. 2012, 134 (44), 18217–18220.
  • Kosal, A. D.; Wilson, E. E.; Ashfeld, B. L., "Phosphine-Based Redox Catalysis in the Direct Traceless Staudinger Ligation of Carboxylic Acids and Azides." Angew. Chem. Int. Ed. 2012, 51 (48), 12036-12040.

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