Professor Thorsten Bach (TUM)

Title: Catalytic Photochemical Deracemization Reactions

Abstract: Photochemistry enables an access to reaction pathways that are not viable in conventional trans­formations. The talk will revolve around the conversion of a racemic mixture to a single enantiomer in a catalytic photochemical deracemization reaction. In an ideal scenario, quantitative yields of enantiomerically pure (>95:5 enantiomeric ratio) compounds can be achieved in a single operation.

The entropically disfavored and thermally impossible process is driven by light energy. The reactions are catalyzed by a single photocatalyst which either acts by energy transfer or by a reversible hydrogen atom transfer. Product classes which have been successfully deracemized by energy transfer include chiral allenes, olefins and cyclopropanes. A reversible hydrogen atom transfer was found to facilitate the deracemization of hydantoins, 3-oxindoles, N-carboxyanhydrides, 2,5-diketopiperazines, aza-1-isoindolinones and chromanes. Possible applications, the underlying mechanistic considerations, and ongoing work on the topic will be presented.

Biography: Thorsten Bach was born in Ludwigshafen/Rhein, Germany. He obtained his education at the University of Heidelberg and the University of Southern California, where he conducted his Diplom thesis with G. A. Olah. He received his Ph.D. in 1991 from the University of Marburg with M. T. Reetz and did postdoctoral work as a NATO fellow with D. A. Evans at Harvard University. He completed his Habilitation at the University of Münster in 1996, moved to the University of Marburg as an associate professor in 1997, and was appointed to his current position as Chair of Organic Chemistry I at the Technische Universität München in 2000. He is an elected member of the German Academy of Sciences Leopoldina since 2006 and the Bavarian Academy of Sciences since 2009. * His research interests revolve around organic photochemistry, enantioselective catalysis, and natural product synthesis.

*Optional:

His latest distinctions include the Gottfried Wilhelm Leibniz prize of the German Science Foundation (DFG), an Arthur C. Cope Scholar Award of the American Chemical Society (ACS), the Ryoji Noyori Prize of the Society of Synthetic Organic Chemistry Japan (SSOCJ), and an Advanced Grant of the European Research Council (ERC).