Enzymatic synthesis of chiral heteroaryl alcohols using plant fragments as the only biocatalyst and reducing agent

Abstract

The enzymatic reduction of prochiral heterocyclic ketones by carrot (Daucus carota) root in water afforded the corresponding S-alcohols in accordance with the Prelog's rule. The reaction was performed under various conditions in order to optimize the procedure of bioreduction regarding reaction time, yield, and optimal mass of carrot. The optimized procedure was used to test the ability of other plants to carry out the reaction. In the latter experiment, it was observed that, with regard to stereospecificity, most vegetables tested were poorer reducing agents compared to D. carota.

Green synthesis of enantiopure (S)‐1‐(benzofuran‐2‐yl)ethanol by whole‐cell biocatalyst

“…Moreover, 50% of the unwanted enantiomer always occurs at kinetic resolution. Aldabalde et al performed the asymmetric reduction of substrate 1 using the D. carota biocatalyst in a shorter reaction time than our study, but their ee and yield were lower than our yield and ee . Salvi et al carried out the asymmetric reduction of substrate 1 using R. arrhizus biocatalyst in a longer reaction time, lower ee and yield than our study .…”

“…The Rhizopus arrhizus mediated bioreduction of 1‐(benzofuran‐2‐yl)ethanone furnished 99.3% ( S )‐1‐(benzofuran‐2‐yl)ethanol, with 91.7% ee . In the literature, it has been reported that 1‐(benzofuran‐2‐yl)ethanone is reduced to ( R )‐benzofuran alcohol by 95% ee and 47% yield with Daucus carota as biocatalyst . In the present study, isolated Lactobacillus paracasei BD87E6 was employed as a whole‐cell biocatalyst in the asymmetric bioreduction of 1‐(benzofuran‐2‐yl)ethanone to ( S )‐1‐(benzofuran‐2‐yl)ethanol in an aqueous medium (Figure ).…”

“…From an industrial point of view, it is very important to work on a large scale; the scale of these two studies in the literature is quite low compared with our study. This study is superior with regard to enantiomeric excess, reaction scale, conversion, and yield compared with the previous studies, which are using biocatalysts …”

Asymmetric Reduction of Heteroaryl Methyl Ketones Using <i>Daucus carota</i>

“…[20,21]. When compared to earlier reports [22][23][24][25], the present study demonstrates that the dehydrogenase enzymes present in D.carota has reduced keto groups attached to five member heteroaryl compounds (1h -1j) (pyrrole, furan and thiophene) with good enantio-selectivity. thus demonstrating the broad specificity of the dehydrogenase enzyme present in the carrot.…”

Plant-Mediated Enantioselective Transformation of Indan-1-One and Indan-1-ol

“…Plant biocatalysts have been applied primarily in the reduction of ketones. [8][9][10][11][19][20][21][22][23][24][25]. Biooxidation of alcohols has been described much less [8,[12][13][14][15]22].…”