Research in the Breugst Group
The Breugst group combines synthetic organic chemistry, kinetic investigations and related physical-organic methods with modern computational techniques to design and understand catalytic reactions. More specifically, we are interested in
- the application of halogen and pnicogen bonding in organocatalysis
- how London dispersion controls organic structures and reactivities
- the elucidation of organic reaction mechanisms
Halogen and Pnicogen Bonding in Organocatalysis
For more than 100 years, molecular iodine is known to be an often outstanding catalyst for many organic transformations but the underlying mode of action was unknown until recently. Our group identified a halogen-bond activation of Michael acceptors as the most likely mechanism. For the first time, we ruled out a hidden Brønsted-acid catalysis as the origin of the catalytic activity of iodine experimentally. We are currently working on applying molecular iodine in other reactions and to design novel halogen-bond donors as catalysts for organic transformations. More information can be found in reviews from our group on iodine catalysis and noncovalent interactions.
Similarly, we are wondering whether a related non-covalent interaction – the pnicogen bond – can also be used in organocatalysis. Computational investigations on model systems indicate that these interactions might be strong enough and we are currently testing this hypothesis experimentally.
London Dispersion, the attractive part of the van-der-Waals force, can have a significant influence on organic structures and reactivities. Consequently, large substituents are not always destabilizing due to a repulsive steric interaction but can contribute to the stabilization of molecules. We are now working on a better understanding on how this interaction controls organic reactivity and on a targeted application in catalysis. A Minireview on this topicfrom our group can be found here (in German).
Elucidation of Reaction Mechanisms
Another research focus of our group is the elucidation of reaction mechanisms based on computational and kinetic investigations. These projects are typically performed in collaboration with various experimental groups around the world and include different fields of organic chemistry including organocatalysis and (transition) metal catalysis. Besides projects dealing with mechanistic or stereochemical questions, we also engage in projects that involve spectroscopic or material aspects.