Fundamentals of Asymmetric Organo-Catalysis

In recent years asymmetric organo-catalysis has emerged as a powerful, metal-free route in enantioselective catalysis, where a chiral organic catalyst is used to control the chirality of a reacting substrate. To date there is little known about the molecular level details of the interaction between the catalyst and the substrate in solution, like binding lifetime and geometry. Due to this lack of fundamental knowledge, optimization of reaction conditions (e.g. solvent, temperature, catalyst, concentrations) is largely based on trial and error. As a consequence, a few hundred different conditions have to be tested in order to optimize the enantiomeric excess of a given catalytic process.

Our current work focuses on determining such fundamental binding parameters (binding strength, binding lifetime, and steric repulsion) in solution. We obtain real-time information on association and binding strength from ultrafast infrared and dielectric spectroscopies. Via systematic correlation of the binding parameters to the enantiomeric excess in a catalytic process, we aim at elucidating the key ingredients for efficient stereocontrol. Such knowledge has the potential to guide optimization of existing catalytic routes and to design of novel catalyses.