Publikationsserver der RWTH Aachen University
Synthesis and application of chiral phosphorous triamide ligands
Abstract
dc:descriptionIn this thesis the synthesis and application of novel chiral monodentate phosphorous triamide (PTA) ligands is presented. First, a small library of chiral PTAs based on three different chiral diamine backbones has been prepared through a convenient modular synthetic approach. The study significantly increases the knowledge about the synthesis, purification, stability and structural features of these compounds. The prepared ligand library was evaluated in the asymmetric hydrogenation as well as in two different asymmetric C-C bond forming reactions. All tested structurally very different PTAs show poor performance in the Rh catalysed hydrogenation of dimethyl itaconate. In contrast, better results could be obtained in the Cu catalysed Michael-addition of diethyl zink to cyclohexenone where enantioselectivity values up to 60% have been achieved. Good conversions, selectivities and promising enantioselectivity of 63% was attained in the Ni catalysed hydrovinylation of styrene at relatively high reaction temperature. The results of this thesis demonstrate that chiral PTAs are accessible and can provide significant levels of enantioselectivity in asymmetric catalysis. Their steric and electronic properties can be fine-tuned by the variation of the amine components. In general, the behaviour of these ligands is significantly different from the related phosphites or phosphoramidites and their potential in enantioselective catalysis is not yet fully explored.
Degree
thesis:*- Grantor dc:publisher
- Publikationsserver der RWTH Aachen University
- Year dc:date
- 2008
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Barta, Katalin
- Contributors dc:contributor
-
- Leitner, Walter
Subjects
dc:subject × 13Rights
dc:rights- Statement dc:rights
-
- info:eu-repo/semantics/openAccess
- Language dc:language
- eng