New methods for the enantiomeric excess determination using NMR

摘要

The synthesis of enantiomerically pure compounds is an important objective of the organic chemistry. Especially in the field of medicine and pesticides, mostly one enantiomer is responsible for the biological activity. Certain examples are known where the other enantiomer is more than isomerical balast, and its presence gives rise to side-effects. It is not surprising that the regulatory authorities in Europe and the United States usually impose that chiral compounds are marketed as single enantiomers. Growing interest and improvement in enantioselective synthesis leads to an increased demand for accurate, reliable and convenient methods of measuring the enantiomeric composition. A large number of methods for the determination of the enantiomeric excess (e.e.) of regardless which chiral substrate have been developed over the years. A popular, accurate, and moreover, fast method for the determination of the enantiomeric composition is to make use of NMR techniques (Nuclear Magnetic Resonance). This thesis describes the research carried out towards the development of new methods for enantiorneric excess determination of amino acids and not naturally occuring α-alkylated amino acids by means of NMR techniques.