Publikationsserver der RWTH Aachen University
Chirale Phosphortriamide und Phosphin-Phosphoramidite als Liganden für die asymmetrische Katalyse
Abstract
dc:descriptionAsymmetric catalysis with transition metal complexes containing chiral ligands is an efficient tool for the synthesis of enantioenriched compounds, which can be used as active pharmaceutical ingredients, agrochemicals, flavors or fragrances. The development of novel chiral ligands plays a major role within the development of efficient catalysts. This thesis is dealing with with synthesis and application of novel chiral phosphorus ligands for asymmetric catalysis. Two different lead structures (phosphorus triamides or phosphine-phosphoramidites respectively) are taken into account. These lead structures are varied via modular synthetic routes. In summary 12 new chiral ligands – 9 phosphorus triamides and 3 phosphine-phosphoramidites – have been synthesised and applied to different enantioselective catalytic transformations. In a first assessment the coordination behaviour of the phosphorus triamides against different transition metal precusors was investigated. In these investigations they exhibited a different behaviour than that known from analogoues phosphoramidites. Based on these observations the ligands were successively tested in a variety of enantioselective transformations in combination with different transition metals. The highest enantiomeric excess obtained was 48% for Ni-catalysed hydrovinylation of styrene. The phosphine-phosphoramidites were especially tested as ligands for asymmetric hydrogenation employing Rhodium or Iridium as the catalytically active metal. In the Rh-catalysed hydrogenation of functionalised olefins high enantiomeric excesses up to 99.6% and a turnover frequency up to 14 100 h-1 were obtained. Furthermore also for the Ir-catalysed hydrogenation of 2-substituted quinolines high enatiomeric excess up to 97% was obtained. In particular the ligand (Sa, Sc)-100 shows a remarkable versatility. Upon application of this ligand quinolines high enantiomeric excess was obtained both in the hydrogenation of functionalised olefins and 2-substituted quinolines.
Degree
thesis:*- Grantor dc:publisher
- Publikationsserver der RWTH Aachen University
- Year dc:date
- 2009
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Eggenstein, Matthias
- Contributors dc:contributor
-
- Leitner, Walter
Subjects
dc:subject × 14Rights
dc:rights- Statement dc:rights
-
- info:eu-repo/semantics/openAccess
- Language dc:language
- ger