Novel fungi-catalyzed reduction of α-alkyl-β-keto esters

Enantioselective Bioreduction of Prochiral Pyrimidine Base Derivatives by Boni Protect Fungicide Containing Live Cells of Aureobasidium pullulans

The enzymatic enantioselective bioreduction of prochiral 1-substituted-5-methyl-3-(2-oxo-2-phenylethyl)pyrimidine-2,4(1H,3H)-diones to corresponding chiral alcohols by Boni Protect fungicide containing live cells of Aureobasidium pullulans was studied. The microbe-catalyzed reduction of bulky-bulky ketones provides enantiomerically pure products (96–99% ee). In the presence of A. pullulans (Aureobasidium pullulans), one of the enantiotopic hydrides of the dihydropyridine ring coenzyme is selectively transferred to the si sides of the prochiral carbonyl group to give secondary alcohols with R configuration. The reactions were performed under various conditions in order to optimize the procedure with respect to time, solvent, and temperature. The present methodology demonstrates an alternative green way for the synthesis of chiral alcohols in a simple, economical, and eco-friendly biotransformation.

Exploiting Enzymatic Dynamic Reductive Kinetic Resolution (DYRKR) in Stereocontrolled Synthesis

Over the past two decades, the domains of both frontline synthetic organic chemistry and process chemistry and have seen an increase in crosstalk between asymmetric organic/organometallic approaches and enzymatic approaches to stereocontrolled synthesis. This review highlights the particularly auspicious role for dehydrogenase enzymes in this endeavor, with a focus on dynamic reductive kinetic resolutions (DYRKR) to "deracemize" building blocks, often setting two stereocenters in so doing. The scope and limitations of such dehydrogenase-mediated processes are overviewed, as are future possibilities for the evolution of enzymatic DYRKR.