Arylated heterocyclic systems, such as fluorophores, have a long history as a component in functional materials. They are extremely useful platforms for a broad application in material science, biological imaging or organic synthesis, owing to their unique chemical, photophysical, and electrochemical properties. The development of an efficient route to prepare this type of heterocycles continues to attract interest for various applications, while only limited to the synthesis of symmetric fluorophores in racemic fashion. Introducing a chiral element into the molecules is of great significance for drug discovery, the design of catalysts for asymmetric synthetic photochemistry and other enantioselective methods. The resulting fluorophore bearing enantiospecific sensing platforms may also find potential applications in the enantioselective recognition of chiral small molecules or bioactive compounds such as DNA. Hence, the aim of the proposed AtropFluoPhoto is to develop a strategy for the asymmetric catalytic synthesis of chiral heterocyclic fluorophores. We plan to investigate different activation modes to achieve the construction of axially chiral fluorophores in intramolecular or intermolecular reactions. With the knowledge of their unique chemical and photophysical properties, we will then particularly explore their practical application in synthesis and novel catalyst design for asymmetric catalysis in photocatalysis.

Structurally well-defined objects are the elements required for the rational design of molecular backbones. The development of novel synthetic methods for the formation of new aromatic rings will provide unique scaffolds, which are not readily accessible otherwise. The catalyst controlled stereoselective arene-forming aldol condensation to form compounds with axial, helical or planar chirality will be investigated in detail. In the examined cascade reactions, the stereochemical information of small amine catalysts is transferred into new chirality elements leading to different, structurally distinct molecular architectures. The well-defined scaffolds will subsequently be employed to position various groups into a predictable spatial arrangement with respect to each other.

The configuration of axially chiral compounds fully governs the biological activity of important pharmaceutical entities and is completely translated from atropisomeric ligands to high-value products in numerous remarkably efficient catalytic processes. However, atroposelective catalysis remained a niche area in the vast field of asymmetric synthesis. This underrepresentation offers intriguing opportunities for the development of novel synthetic methods and strategies. Inspired by the aromatic polyketide biosynthesis, the proposed method takes advantage of an aromatization as ample driving force and utilizes efficient transfer of central to axial chirality from the catalyst to the product. Readily available substrates will be treated with secondary amine organocatalysts to initiate a cyclization event, inducing an aromatization process to selectively form the desired atropisomer after release of the catalyst.