Cooperative Asymmetric Catalysis
Almost every complex chiral enantiopure chemical entity can nowadays be prepared by synthetic chemists given ample time and resources. However, the existing catalytic asymmetric methods are often not efficient enough from a practical or technical point of view, suffer from a severe lack of generality and do not match the efficiency achieved by Nature in the last. While analyzing the current situation of asymmetric catalysis in production processes, it becomes evident that applications on a technical scale –for instance in pharmaceutical industry– are largely limited to asymmetric hydrogenations and few enzyme catalyzed processes.
The major research efforts of our synthetically oriented group are thus structured around the development of innovative catalytic asymmetric methods to provide general solutions for long-standing synthetic problems. We are interested in the precise control over chemical reactivity and stereoselectivity by our artificial catalysts to synthesize high-value-added functionalized building blocks with a high level of efficiency. The catalyst systems should be readily accessible and the catalytic procedures operationally simple in order to develop practical methods, which ideally have the potential for large scale applications.
In our research program we incorporate a central strategy using Nature as our guide to overcome these limitations: cooperative catalysis. Cooperative catalysis means that various functional groups of a catalyst system work in concert to accelerate and control a chemical process, similar to the way enzymes act. Unlike Nature which makes use of sophisticated and specialized active sites embedded within a huge enzyme machinery evolved over billions of years from so simple in the beginning, we try to mimic their complex operating mode relying on the interplay of various electronic and steric interactions between the substrates and tailor-made bi- or polyfunctional low molecular weight catalysts. Both substrates –electrophile and nucleophile– should be simultaneously activated in close spatial proximity to achieve high catalytic activity under mild conditions. Moreover, interaction of the various activating functional groups of the catalyst with the substrates should effectively preorganize the reactants in space in the chiral environment of the active site thus allowing for excellent levels of stereoselectivity. To understand the relevant interactions through mechanistic studies is always a goal in order to allow to predict results and to rationally develop new applications for the streamlined synthesis of complex molecules.
For details please go to publications.