P-Chiral Phosphorus Ligands: Synthesis and Application in Asymmetric Hydrogenation (English shop)

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The dissertation “P-Chiral Phosphorus Ligands: Synthesis and Application in Asymmetric Hydrogenation” by Björn Gschwend investigates the synthesis and catalytic applications of phosphorus-chiral ligands.
A central focus is the development of stereoselective synthetic routes to novel ferrocenephospholanes.
Starting from Ugi’s amine, chiral phosphine ligands are prepared through diastereoselective ortho-lithiation and intramolecular hydrophosphination.
The synthesized compounds are investigated regarding their coordination properties and catalytic performance.
Particular attention is given to the asymmetric hydrogenation of different olefins using rhodium and iridium complexes.
The influence of ligand structure and metal coordination on catalytic activity and selectivity is systematically examined.
The results demonstrate that the developed ferrocenephospholanes cannot compete with established catalyst systems in terms of activity and selectivity.
Additionally, P-chiral secondary phosphine oxides are synthesized from terpene-based starting materials.
A borneol-derived ligand achieves enantiomeric excesses of up to 93% in rhodium-catalyzed hydrogenation.
Further investigations include hydroxyethyl-functionalized phosphines and menthol-derived phosphino-oxazoline-iridium complexes.
The latter exhibit high catalytic activity, although their enantioselectivities generally remain below those of previously reported PHOX systems.
The findings provide insights into structure–activity relationships and the development of chiral ligand systems for asymmetric catalysis.