Oxidopyrylium-Based {5+2} Cycloadditions: A Superb Platform for Training Next Generation Scientists

CHEM295- "Chem Seminars"

Join the students of CHEM295, "Chem Seminars", as they welcome guest speakers and presenters onto campus to learn about their unique work within the fields of chemistry and biochemistry. Learn about the numerous research projects, interesting developments, and dedication to their work that our presenters share with Calvin students, demonstrating how the sciences impact their call for service in the world.

Thursday, Sept. 23rd, 2021

11:30a - 12:20p

Science Building (SB)110

Title: "Oxidopyrylium-Based {5+2} Cycloadditions: A Superb Platform for Training Next Generation Scientists"

Guest Speaker: Andy Mitchell- Illinois State University

We train next generation scientists by guiding them through important research questions in the realm of oxidopyrylium-based [5+2] cycloadditions. Initial efforts probed the mechanism of formation and cycloaddition of oxidopyrylium intermediates, which led to a [5+2] cycloaddition conjugate addition cascade (C3) sequence in which 3 new rings, 4 new bonds, and 6 new stereocenters were constructed with high selectivity. In collaboration with the Tantillo group, several experimental observations were corroborated via calculations including evidence for the RDS of deprotonation and Kinetic Isotope Effects that matched our 2H-labeling experiments. In addition, we have discovered a superior silyl transfer group (i.e. TBDPS) in silyloxypyrone-based [5+2] cycloadditions that may proceed through a variety of mechanisms and have opened new avenues including room temperature cycloadditions. Specifically, oxidopyrylium-enamine [5+2] cycloaddition with a proline derivative gave 4 new stereocenters with excellent selectivity at ambient temperature. We have also explored applications such as efforts toward the total synthesis of toxicodenane A in which we utilized an oxidopyrylium-based [5+2] cycloaddition of a silicon-tethered BOC-pyranone. We will continue to build on this work toward mechanistic investigations, new reaction development, and the synthesis of biologically relevant small molecules. Within this framework, next generation scientists will be trained to ask important questions in the context of this fascinating discipline of organic synthesis.

Information about the Guest Speaker

Andy Mitchell earned his B.S. at Grove City College (PA) and his Ph.D. at Texas A&M University in 2008 with Prof. Daniel Romo. He was a postdoctoral associate at the University of Pennsylvania with Prof. Jeffrey Bode before joining the ISU Chemistry Department as an Assistant Professor in August 2010. He was promoted to Associate Professor with tenure in August 2016 and then Professor in August 2021. His research group focuses on natural products inspired organic synthesis in the context of training next-generation scientists to ask important questions. Outside of chemistry, Andy enjoys spending time with his wife and three kids.