The Utility of Modified Cyclodextrin, Sol-Gel Procedure and Gas Chromatography in Lipase-mediated Enantioselective Catalysis : Kinetic Resolution of Secondary Alcohols

The scope of this thesis is a trial to find a suitable way to overcome the disadvantages accompanied to the use of lipases in organic solvents. This was based on the use of macrocyclic additives (e.g. modified and free cyclodextrins) and immobilized methods (e.g. sol-gel procedure) to enhance the conversion and enantiomeric ratio in lipase-catalyzed transesterification in organic solvent. The modified methods were used in the production of enantiomerically pure compounds used as chiral building blocks such as1-(2-furyl)ethanol, trans-4-phenyl-3-butene-2-ol and menthol. Attempts to find a suitable innocuous acyl donor and to produce enantiomers in gram scale and in high enantiomeric excess using lipase-catalyzed kinetic resolution of the racemic substrate is also considered. To render the kinetic resolution of secondary alcohols efficient in the production of enantiomerically pure compounds, gas-chromatography was used in the determination of the enantiomeric excesses of substrates and products resulting from the enzymatic resolution.Das Ziel der Arbeit war es, eine Methode zur Lipase-katalysierten kinetischen Racematspaltung von sekundären Alkoholen zu entwickeln. Eine Verbesserung des Enantiomerenverhälnisses und des Umsatzes wurde durch Einsatz von Cyclodextrinderivaten als Additiv bzw. des Sol-Gel-Prozesses erreicht. Zur Bestimmung des jeweiligen Enantiomerenüberschusses wurde enantioselektive Gas-Chromatographie benutzt