Abstract
dc:descriptionChiral alpha-ketoacids and their derivatives play an important role in organic synthesis and are widely used as inhibitors of both proteolytic enzymes as well as inhibitors of leukotriene A4 hydrolase. Furthermore they are an integral part of important biologically active ulosonic- and sialic acids. Because of the presence of an beta-enolisable asymmetric centre, the number of methods leading to enantioenriched alpha-ketoesters are rather limited. New and efficient synthetic approaches as a solution to this problem are therefore of high interest. This thesis deals with the application of chiral and racemic glyoxylate aminonitriles in developing both a stoichiometric as an organocatalytic procedure for the synthesis of beta-substituted alpha-ketoesters. This could be realised by applying the concept of Umpolung, which enables the nucleophilic introduction of the alpha-ketoacid system. The use of chiral glyoxylate aminonitriles in the Michael addition to nitroalkenes and subsequent cleavage of the aminonitrile group led to the corresponding gamma-nitro-alpha-ketoesters in high enantiomeric excesses. An asymmetric organocatalytic approach to protected beta-substituted delta-hydroxy-alpha-ketoesters with good enantio- and diastereoselectivities could be realised in the presence of a diphenylprolinol catalyst.
Degree
thesis:*- Grantor dc:publisher
- Mainz
- Year dc:date
- 2007
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Bonten, Maurice Hubert
- Contributors dc:contributor
-
- Enders, Dieter
Subjects
dc:subject × 15Rights
dc:rights- Statement dc:rights
-
- info:eu-repo/semantics/openAccess
- Language dc:language
- ger
Identifiers
dc:identifier.*- OAI identifier oai:identifier
- oai:publications.rwth-aachen.de:61714