Effenberger, FranzGutterer, BeateZiegler, ThomasEckhardt, ElisabethAichholz, Reiner2009-08-272016-03-312009-08-272016-03-311991312110731http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-43875http://elib.uni-stuttgart.de/handle/11682/1153http://dx.doi.org/10.18419/opus-1136In der vorliegenden Arbeit berichten wir zusammenfassend über die enantioselektive Hydrolyse oder enantioselektive Umesterung racemischer Cyanhydrinester und über die enantioselektive Veresterung racemischer Cyanhydrine mittels Lipasen.Pure cyanohydrin enantiomers (S)-1/(R)-1 and their O-acyl derivatives (R)-3/(S)-3 are obtained from three different lipasecatalyzed reactions: i) enantioselective hydrolysis of aliphatic and aromatic racemic cyanohydrin esters 3, ii) enantioselective acylation of racemic cyanohydrins 1, iii) enantioselective transesterification of 3 with primary alcohols. Both the cyanohydrin esters and the free cyanohydrins (which are prone to racemization) are isolated as enantiomers with high optical purity on a preparative scale. Hydrolysis of the racemic butyrates 3b, e with Candida cylindracea lipase and pseudomonas sp. lipase, respectively, for example, affords the free (S)-cyanohydrins (S)-2-hydroxypentanenitril [(S)-1a] and (S)-mandelonitrile [(S)-1b)] in high yield with 97 and 96% ee, respectively. (S)-1a is obtained with the same optical purity by candida sp. lipase-catalyzed transesterification of 3b with 1-octanol.deinfo:eu-repo/semantics/openAccessEnzymkatalyse , Racemisierung540article2010-01-19