Biocatalytic preparation of optically active 4-(N,N-dimethylamino)pyridines for application in chemical asymmetric catalysis
摘要:
4-Chloro-2-(1-hydroxybenzyl)pyridine and 4-chloro-2-(1-hydroxyalkyl)pyridines were obtained with moderate to excellent enantiomeric excesses and high isolated yields by bioreduction with Baker's yeast of the corresponding ketones. The resulting optically active alcohols were transformed into adequate DMAP derivatives, which have been applied in asymmetric catalytic processes as nucleophilic catalysts in the stereoselective chemical alkoxycarbonylation of 1-phenylethanol or as chiral ligands in the enantioselective addition of diethylzinc to benzaldehyde. (c) 2006 Elsevier Ltd. All rights reserved.
Chemoenzymatic synthesis of chiral 4-(N,N-dimethylamino)pyridine derivatives
摘要:
Chiral 4-(N,N-dimethylamino)pyridine derivatives have been prepared through a chemoenzymatic synthesis where the enzymatic kinetic resolution of a family of 4-chloro-2-(1-hydroxyalkyl)pyridines is the key step for the formation of potentially important chiral catalysts. Pseudomonas cepacia lipase (PSL) showed excellent enantioselectivity in the acylation of the (R)-enantiomers (E > 200) using vinyl acetate as acylating agent and THF as solvent, obtaining products and substrates enantiomerically pure and with excellent yields. (c) 2005 Published by Elsevier Ltd.
An enantioselective, catalytic trichloromethylation of 2-acyl imidazoles and 2-acylpyridines is reported. Several products are formed with enantiomeric excess of ≥99%. In this system, a chiral iridium complex serves a dual function, as a catalytically active chiral Lewis acid and simultaneously as a precursor for an in situ assembled visible-light-triggered photoredox catalyst.
set of transaminases has been investigated for the biocatalytic amination of 1-(4-chloropyridin-2-yl)alkan-1-ones. The influence of the chain length of the n-1-alkanone at the C-2 position of the pyridine has been studied in the reaction with different (R)- and (S)-selectivetransaminases. Thus, enantiopure amines were isolated with high purity starting from a wide selection of prochiral ketones. On the
Quantitative dynamic capsule–capsule conversion by cooperative binding one carbonate anion and switchable dual catalysis was achieved within an Ir2Co3-type capsule.
通过在Ir2Co3型胶囊内协同结合一个碳酸根离子和可切换的双重催化,实现了定量动态胶囊-胶囊转化。
Chemoenzymatic synthesis of chiral 4-(N,N-dimethylamino)pyridine derivatives
Chiral 4-(N,N-dimethylamino)pyridine derivatives have been prepared through a chemoenzymatic synthesis where the enzymatic kinetic resolution of a family of 4-chloro-2-(1-hydroxyalkyl)pyridines is the key step for the formation of potentially important chiral catalysts. Pseudomonas cepacia lipase (PSL) showed excellent enantioselectivity in the acylation of the (R)-enantiomers (E > 200) using vinyl acetate as acylating agent and THF as solvent, obtaining products and substrates enantiomerically pure and with excellent yields. (c) 2005 Published by Elsevier Ltd.
Biocatalytic preparation of optically active 4-(N,N-dimethylamino)pyridines for application in chemical asymmetric catalysis
4-Chloro-2-(1-hydroxybenzyl)pyridine and 4-chloro-2-(1-hydroxyalkyl)pyridines were obtained with moderate to excellent enantiomeric excesses and high isolated yields by bioreduction with Baker's yeast of the corresponding ketones. The resulting optically active alcohols were transformed into adequate DMAP derivatives, which have been applied in asymmetric catalytic processes as nucleophilic catalysts in the stereoselective chemical alkoxycarbonylation of 1-phenylethanol or as chiral ligands in the enantioselective addition of diethylzinc to benzaldehyde. (c) 2006 Elsevier Ltd. All rights reserved.