Helically-shaped peri-oligo-naphthylenes and organophotocatalytic flow oxygenation of phenols

Helically-Shaped peri-Oligo-Naphthylenes
The development of helically-shaped peri-oligonaphthylenes represents a significant advancement in the field of molecular systems, offering unique structural motifs with promising applications in organic synthesis and material science. In this thesis, the synthesis and structural characterization of multiaxial peri-oligonaphthylenes are explored, aiming to elucidate their unique architecture. Leveraging Suzuki–Miyaura cross-coupling sequences, a selection of peri-oligonaphthylenes with various chain elongation building blocks is successfully synthesized. Notably, substrate-controlled diastereoselectivity was observed during the Miyaura-borylation of substrates. X-ray analysis of an advanced structure provides valuable structural information, confirming the all-trans configuration of specific motifs. These structurally intriguing, configurationally stable oligomers could potentially serve as valuable scaffolds, facilitating the precise and predictable placement of substituents within a defined spatial relationship.
Catalytic Combes Reaction to Access 4-Arylquinolines
Quinolines represent an important class of heterocyclic nitrogen-based compounds with prevalent structures in natural products and hold immense promise in drug discovery and biological research. Consequently, devising a catalytic synthetic route to access these molecules is crucial. In this study, an organocatalytic Combes quinoline reaction is presented using readily accessible building blocks and anilines. The resulting heterobiaryl compounds could, upon further modification, potentially serve as platform for catalysis as ligands or aid in the development of synthetic methodologies for new pharmaceutical agents.
Organophotocatalytic Flow Oxygenation of Phenols
In response to the environmental challenges posed by large-scale vitamin E production, which relies on benzoquinone building blocks, a critical demand for a sustainable alternative has emerged. Current processes involve harsh conditions and generate substantial amounts of detrimental metal waste, causing environmental pollution. To tackle this issue, an eco-friendly approach is proposed, utilizing a mild organophotocatalytic phenol oxygenation method with a cost-effective organophotocatalyst under visible light and air overpressure conditions. Products for diverse applications, encompassing the synthesis of vitamins and a prodrug, were obtained in high yields by means of a simple modular continuous flow photoreactor set-up with precise control panels. The reactor design permits the use of low photocatalyst loadings to promote singlet oxygen generation. This approach is expected to contribute to a circular economy and sustainable synthesis by facilitating the efficient gas-liquid reaction for the high-yielding formation of quinones with air, thereby avoiding the production of hazardous metal waste streams and the use of chlorinated solvents.