Multifunctional BINOL-phosphates as anionic phase-transfer catalysts for asymmetric organocatalysis

• Applicant: Professor Dr. Jochen Niemeyer
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 544140417

This research project will deliver novel chiral phosphates that function as organocatalysts in the asymmetric anionic phase-transfer catalysis. With these catalysts, we will enable Selectfluor-based asymmetric electrophilic fluorination reactions and also develop the use of alternative electrophiles to systematically extend the range of applications of anionic phase transfer catalysts. To reach these aims, we will synthesize catalysts that feature two covalently linked BINOL-phosphates. Such dianionic phase-transfer catalysts are ideally suited for interaction with dicationic electrophiles such as Selectfluor. The introduction of different substituents and different linkers in the catalyst structures will deliver an initial library of catalysts. As a next step, we will generate heterofunctional catalysts that contain additional amine- or thiourea-groups, allowing for a directed interaction with the nucleophile next to the phosphate-electrophile interaction. A detailed analysis of the underlying reaction mechanisms in catalysis, with a special focus on aggregation processes, will enable a further optimization of the catalytic reaction conditions. Based on these insights, we aim for enabling electrophilic fluorination reactions in excellent enantioselectivities. Next, we will try to extend the applicability of anionic phase-transfer catalysts by using alternative electrophiles that allow for introduction of carbon- or sulfur-substituents. This will enable the construction of quaternary carbon-stereocenters. Finally, we will demonstrate the applicability of these newly developed methodologies based on the enantioselective synthesis of pharmaceutically relevant steroids such as Izonsteride.

• DFG Programme: Research Grants