Application of asymmetric biocatalysis to organic chemistry

Yeuk-Chuen Liu, University of Rhode Island

Abstract

Recently, asymmetric biocatalysis has received much attention, particularly in the area of enantioselective lipase catalysis. Basic principles governing the stereochemical selectivity of lipase catalysis are addressed in this thesis and their applications to the preparation of optically active molecules are also discussed.^ Ibuprofen undergoes unidirectional metabolic inversion from the inactive R-isomer to the S-antipode. A NMR approach is being used to study this metabolic reaction. Optically pure ibuprofen labelled with $\sp{13}$C and $\sp2$H at C-2 position has been synthesized using a chemo-enzymatic method. The preliminary $\sp{13}$C-NMR study on the metabolism of ibuprofen CoA thioester in mitochondria is described.^ D-Myo-inositol polyphosphates are important second messengers. The 1,4,5-tris-, 1,3,4-tris-, and 1,3,4,5-tetrakis-phosphates of D-myo-inositol have been prepared in their enantiomerically pure forms from the two enantiomers of 1,2:5,6-di-O-cyclohexylidene-myo-inositol.^ Computer modelling has proved to be a useful tool for substrate design in biocatalytic resolution. N-butyryl-O-methoxycarbonyl-propranolol, is designed by computer analysis to afford optically enriched propranolol.^ $\alpha$-Hydroxy tosylates are key intermediates for the preparation of optically active 1,2-epoxides. Several optically active $\alpha$-hydroxy tosylates are prepared by two different modes of lipase-catalyzed transesterification in organic solvent.^ Generally, the enhancement of enzymatic enantioselectivty can be achieved by: either changing the reaction conditions or modifying the substrate. It is shown in this thesis that the synergistic coupling of lipase-mediated enantiospecific reactions of deacylation and esterification allows optical purity enhancement in the resolution of racemic alcohols. ^

Subject Area

Chemistry, Organic

Recommended Citation

Yeuk-Chuen Liu, "Application of asymmetric biocatalysis to organic chemistry" (1992). Dissertations and Master's Theses (Campus Access). Paper AAI9239576.
http://digitalcommons.uri.edu/dissertations/AAI9239576

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