Abstract
Several 4-aryl- and 4-heteroarylbut-3-en-2-ones (2a-c, bearing 4-phenyl-, 4-(furan-2-yl)- and 4-(1-benzyl-1H-indol-3yl)-substituents, respectively) were prepared by condensation reaction of acetone with the corresponding aldehydes (1a-c). Reduction of the ketones (2a,b) with NaBH4 resulted in the formation of the corresponding racemic secondary alcohols (rac-3a,b). On the other hand, reduction of the ketone bearing indole moiety (2c) gave an unstable product. The lipase-catalyzed enantiomer selective acetylation of the alcohols (rac-3a,b) by vinyl acetate has been investigated with a crude lipase from submerged fermentation (SmF) of a thermophilic fungus, with several crude enzyme preparations from solid state fermentation (SSF) of selected mesophilic fungi and with several commercially available lipases. The commercial and SmF lipases and the majority of SSF preparations exhibited high but usual enantiomer selectivities and resulted in the formation of (R)-acetates ((R)-4a,b) according to the Kazlauskas' rule. Several SSF preparations, however, behaved as selective anti-Kazlauskas catalysts.
Highlights
There is an ever growing demand in the pharmaceutical and fine chemical industry for production of optically active intermediates
Lipases are suited for the kinetic resolution of secondary alcohols, since these enzymes exhibit high stability and enantioselectivity in organic solvents, and they are environmentally friendly.[5]
As the secondary alcohols in this study contained rigid or more flexible ring adjacent to the asymmetric carbon centre,[7] one of our aims was to broaden the selection of the substrates for these solid state fermentation (SSF) preparations by studying the kinetic resolution of allylic alcohols containing the rings at more remote position from the asymmetric center
Summary
There is an ever growing demand in the pharmaceutical and fine chemical industry for production of optically active intermediates. In this area, biocatalysis has expanded from a niche technology to a widely used manufacturing method.[1] Biocatalysts − enzymes and whole-cell systems − as a result of their chiral nature are predominantly suited for production of optically pure stereoisomers. The commercial availability of a range of lipase preparations at low cost has widely expanded their use as biocatalysts in organic chemistry
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
