The effect of benzyl amine on the efficiency of the base-catalyzed transamination of α-keto esters
摘要:
This paper describes the effect of benzyl amine on the base-catalyzed transamination of alpha-keto esters. Among various benzyl amines examined, o-HOC6H4CH2NH2 was found to be highly effective for the reaction, affording a wide variety of alpha-amino esters in good yields. The o-OH group of the benzyl amine facilitates the transamination process likely via H-bond. Moderate enantiomeric excess was obtained for alpha-amino ester when a quinine derived catalyst was used. (C) 2012 Elsevier Ltd. All rights reserved.
Reaction design in asymmetric catalysis has traditionally been predicated on a structurally robust scaffold in both substrates and catalysts, to reduce the number of possible diastereomeric transition states. Herein, we present the stereochemical dynamics in the Ni(II)-catalyzed diastereoconvergent (3 + 2) cycloadditions of isomerizable nitrile-conjugated nitrones with α-ketoesterenolates. Even in
Asymmetric Synthesis of Diverse Glycolic Acid Scaffolds via Dynamic Kinetic Resolution of α-Keto Esters
作者:Kimberly M. Steward、Michael T. Corbett、C. Guy Goodman、Jeffrey S. Johnson
DOI:10.1021/ja3102709
日期:2012.12.12
The dynamickineticresolution of α-keto esters via asymmetric transfer hydrogenation has been developed as a technique for the highly stereoselective construction of structurally diverse β-substituted-α-hydroxy carboxylic acid derivatives. Through the development of a privileged m-terphenylsulfonamide for (arene)RuCl(monosulfonamide) complexes with a high affinity for selective α-keto ester reduction
Enantioselective mono‐fluorination of α‐keto esters was achieved using a mildly basic palladium μ‐hydroxo complex as catalyst. Subsequent one‐pot reduction afforded optically active β‐fluoro‐α‐hydroxy esters. These compounds were then converted into β‐fluoro‐α‐amino esters, which are potentially useful in medicinal chemistry research.
Nickel(II)‐Catalyzed Diastereo‐ and Enantioselective Michael/ Hemiacetalization Cascade Reaction of α‐Ketoesters with 2‐(2‐Nitrovinyl)phenols
作者:Long Chen、Wu‐Lin Yang、Jia‐Huan Shen、Wei‐Ping Deng
DOI:10.1002/adsc.201900753
日期:2019.10.8
A nickel(II)/diamine‐catalyzed diastereo‐ and enantioselective Michael/hemiacetalization cascade reaction of α‐ketoesters with 2‐(2‐nitrovinyl)phenols has been established, thus providing a range of structurally diverse polysubstituted chromanes in good yields and excellent stereoselectivities (up to 89% yield, >20:1 dr, >99% ee). Moreover, the gram‐scale experiment was performed with only 0.5 mol%
An Efficient Asymmetric Biomimetic Transamination of α-Keto Esters to Chiral α-Amino Esters
作者:Xiao Xiao、Mao Liu、Chao Rong、Fazhen Xue、Songlei Li、Ying Xie、Yian Shi
DOI:10.1021/ol302427d
日期:2012.10.19
An efficient asymmetric biomimetic transamination of α-ketoesters with quinine derivatives as chiral bases was described. A wide variety of α-amino esters containing various functional groups can be synthesized in high yield and enantioselectivity.