Enantioselective biotransformation of α,α-disubstituted dinitriles to the corresponding 2-cyanoacetamides using Rhodococcus sp. CGMCC 0497
摘要:
A new application of nitrile-converting enzymes in the synthesis of optically active alpha,alpha-disubstituted-alpha-cyanoacetamides from alpha,alpha-disubstituted-malononitriles with whole cells of Rhodococcus sp. CGMCC 0497 is described. The products were obtained with enantiomeric excesses of up to >99%, and yields of up to 53%. They are very useful chiral intermediates especially for the synthesis of chiral alpha,alpha-disubstituted amino acids but have never been synthesized directly by chemical or enzymatic methods. (C) 2003 Elsevier Ltd. All rights reserved.
Practical Synthesis of Optically Active α,α-Disubstituted Malonamic Acids through Asymmetric Hydrolysis of Malonamide Derivatives with Rhodococcus sp. CGMCC 0497
摘要:
A variety of alpha,alpha-disubstituted malonamides undergo enantioselective hydrolysis with Rhodococcus sp. CGMCC 0497 to give challenging enantiopure alpha,alpha-disubstituted malonamic acids with up to >99% enantiomeric excesses and 98% chemical yields. The enantioselectivity originated from the effects of a highly enantioselective amidase. The products could be converted to valuable (R)or (S)-alpha,alpha-dialkylated amino acids after routine conversions.
Highly enantioselective synthesis of α,α-disubstituted malonamic acids through asymmetric hydrolysis of dinitriles with Rhodococcus sp. CGMCC 0497Electronic supplementary information (ESI) available: full experimental details. See http://www.rsc.org/suppdata/cc/b2/b210743k/
作者:Zhong-Liu Wu、Zu-Yi Li
DOI:10.1039/b210743k
日期:2003.1.23
Highly enantioselective hydrolysis of α,α-disubstituted malononitriles by the strain Rhodococcus sp. CGMCC 0497 expressing both nitrile hydratase and amidase activity to give (R)-α,α-disubstituted malonamic acids which could be converted to valuable (R)- or (S)-α-alkylated amino acids are reported and the yields of the products are improved remarkably at a lower reaction temperature.
The asymmetric hydration of alpha-benzyl-alpha-methylmalononitrile was examined by using chiral bifunctional catalysts. Enantiomer discrimination of the prochiral dinitrile in the presence of water was demonstrated with a well-defined bifunctional amido-Ru complex having N-sulfonyldiamine ligands, and providing the corresponding amidato(amine) complexes diastereoselectively. Under the catalytic conditions, the (R)-cyanoamide was successfully obtained without further hydrolysis to carboxylic acids. (C) 2010 Elsevier Ltd. All rights reserved.