Highly Enantioselective Hydrogenation of Quinolines Using Phosphine-Free Chiral Cationic Ruthenium Catalysts: Scope, Mechanism, and Origin of Enantioselectivity
作者:Tianli Wang、Lian-Gang Zhuo、Zhiwei Li、Fei Chen、Ziyuan Ding、Yanmei He、Qing-Hua Fan、Junfeng Xiang、Zhi-Xiang Yu、Albert S. C. Chan
DOI:10.1021/ja2023042
日期:2011.6.29
Asymmetric hydrogenation of quinolines catalyzed by chiral cationic η(6)-arene-N-tosylethylenediamine-Ru(II) complexes have been investigated. A wide range of quinoline derivatives, including 2-alkylquinolines, 2-arylquinolines, and 2-functionalized and 2,3-disubstituted quinoline derivatives, were efficiently hydrogenated to give 1,2,3,4-tetrahydroquinolines with up to >99% ee and full conversions
已经研究了由手性阳离子 η(6)-芳烃-N-甲苯磺酰乙二胺-Ru(II) 配合物催化的喹啉的不对称氢化。广泛的喹啉衍生物,包括 2-烷基喹啉、2-芳基喹啉和 2-官能化和 2,3-二取代的喹啉衍生物,被有效氢化得到 1,2,3,4-四氢喹啉,ee 高达 >99%和完全转换。该催化方案适用于一些具有生物活性的四氢喹啉的克级合成,如 (-)-angustureine 和 6-fluoro-2-methyl-1,2,3,4-tetrahydroquinoline,这是制备的关键中间体抗菌剂(S)-氟甲喹。该反应的催化途径已使用化学计量反应、中间体表征、和同位素标记模式。从这些实验中获得的证据表明,喹啉通过离子和级联反应途径被还原,包括 1,4-氢化物加成、异构化和 1,2-氢化物加成,并且氢加成经历了逐步的 H(+)/H( -) 协调范围之外的转移过程而不是协调机制。此外,DFT 计算表明,对映选择性源自