A highly enantioselective iridium-catalyzed hydrogenation of α-keto amides to form α-hydroxy amides has been achieved with excellent results (up to >99% conversion and up to >99% ee, TON up to 100 000). As an example, this protocol was applied to the synthesis of (S)-4-(2-amino-1-hydroxyethyl)benzene-1,2-diol, the enantiomer of norepinephrine, which is widely used as an injectable drug for the treatment
Effects of organic solvents and ionic liquids on the aminolysis of (RS)-methyl mandelate catalyzed by lipases
作者:Cristiane Pilissão、Maria da Graça Nascimento
DOI:10.1016/j.tetasy.2006.02.001
日期:2006.2
The enzymatic resolution of (RS)-methyl mandelate with n-butylamine using lipases in organic solvents (n-hexane, tert-butanol, and chloroform) and ionic liquids [BMIm][BF4] and [BMIm][PF6] is reported. The amide configuration is dependent on the organic solvent. When using mixtures of chloroform or tert-butanol/ionic liquids (10: 1 v/v) with CAL-B as the catalyst, the amides were obtained in high enantiomeric excess (ee(p) > 99% and E > 200). (c) 2006 Elsevier Ltd. All rights reserved.