Lu Yingdong, Johnstone Tim C, Arndtsen Bruce A
Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 2K6, Canada.
J Am Chem Soc. 2009 Aug 19;131(32):11284-5. doi: 10.1021/ja904185b.
While asymmetric transition-metal catalysis has become a powerful method for constructing chiral products, a challenge in this field is the identification of the correct ligand for high selectivity. We report here a simple approach to chiral catalyst formation: coupling of an available pool of Brønsted acids, namely, amino acid derivatives, with tunable ligands on copper catalysts. This system can be used to generate many different chiral environments simply by changing the amino acid or ligand employed and provides a scaffold for rapid screening and identification of the correct combination for high enantioselectivity. The latter is illustrated in the copper-catalyzed alkynylation of imines in up to 99% ee.
虽然不对称过渡金属催化已成为构建手性产物的有力方法，但该领域的一个挑战是识别具有高选择性的正确配体。我们在此报告一种形成手性催化剂的简单方法：将一组现成的布朗斯特酸（即氨基酸衍生物）与铜催化剂上的可调配体进行偶联。通过简单地改变所用的氨基酸或配体，该体系可用于生成许多不同的手性环境，并为快速筛选和识别高对映选择性的正确组合提供了一个框架。后者在铜催化的亚胺炔基化反应中得到了体现，对映体过量值高达99%。
