The Dynamic Kinetic Resolution of Azlactones with Thiol Nucleophiles Catalyzed by Arylated, Deoxygenated Cinchona Alkaloids
摘要:
A significant improvement of the available organocatalytic methods (in terms of product substrate scope and product enantiomeric excess) for the generation of enantioenriched alpha-amino acid thioesters via the dynamic kinetic resolution of azlactones is reported. C-9 arylated cinchona alkaloid catalysts have been found to be considerably superior to other bifunctional alkaloid catalysts as the promoters of this asymmetric process.
Highly tunable arylated cinchona alkaloids as bifunctional catalysts
作者:Cormac Quigley、Zaida Rodríguez-Docampo、Stephen J. Connon
DOI:10.1039/c1cc14684j
日期:——
We report the design and evaluation of a library of chiral bifunctional organocatalysts in which the distance between the catalytically active units can be systematically varied.
我们报道了一种手性双功能有机催化剂库的设计与评估,其中催化活性单元之间的距离可以系统地变化。
C-5′-Substituted Cinchona Alkaloid Derivatives Catalyse the First Highly Enantioselective Dynamic Kinetic Resolutions of Azlactones by Thiolysis
作者:Carole Palacio、Stephen J. Connon
DOI:10.1002/ejoc.201300451
日期:2013.8
The highly enantioselective dynamickineticresolution (DKR) of azlactones by thiolysis has been achieved for the first time. Although both the parent alkaloid quinine and known C-5′-urea derivatives fail to promote the reaction effectively, a new class of C-5′-hydroxylated catalysts proved capable of catalysing the DKR of a range of azlactones derived from both unbranched- and, previously challenging
首次实现了硫解对吖内酯的高度对映选择性动态动力学拆分 (DKR)。尽管母体生物碱奎宁和已知的 C-5'-尿素衍生物都不能有效地促进反应,但证明了一类新的 C-5'-羟基化催化剂能够催化一系列衍生自无支链和无支链的吖内酯的 DKR。 ,以前具有挑战性的 84-92% ee 的支链氨基酸,包括合成富含对映体的 N 保护硫酯的例子,该硫酯来源于从默奇森陨石中分离的外星氨基酸。