Asymmetric Hydrogenation of 2- and 2,3-Substituted Quinoxalines with Chiral Cationic Ruthenium Diamine Catalysts
作者:Jie Qin、Fei Chen、Ziyuan Ding、Yan-Mei He、Lijin Xu、Qing-Hua Fan
DOI:10.1021/ol2029096
日期:2011.12.16
The enantioselective hydrogenation of 2-alkyl- and 2-aryl-subsituted quinoxalines and 2,3-disubstituted quinoxalines was developed by using the cationic Ru(η6-cymene)(monosulfonylated diamine)(BArF) system in high yields with up to 99% ee. The counteranion was found to be critically important for the high enantioselectivity and/or diastereoselectivity.
together! A selective Fe‐catalysed enantioselective reduction of quinoxalines and benzoxazines with hydrogen is demonstrated. Key to success is the combination of a chiral Brønsted acid and a well‐defined non‐chiral Fe hydrogenation catalyst. This methodology constitutes an attractive and environmentally favourable alternative to well‐established asymmetric hydrogenations by using precious‐metal‐based catalysts
General Asymmetric Hydrogenation of 2-Alkyl- and 2-Aryl-Substituted Quinoxaline Derivatives Catalyzed by Iridium-Difluorphos: Unusual Halide Effect and Synthetic Application
A general asymmetric hydrogenation of a wide range of 2-alkyl- and 2-aryl-substituted quinoxaline derivatives catalyzed by an iridium–difluorphos complex has been developed. Under mild reaction conditions, the corresponding biologically relevant 2-substituted-1,2,3,4-tetrahydroquinoxaline units were obtained in high yields and good to excellent enantioselectivities up to 95%. With a catalyst ratio
已开发出由铱-二氟配合物催化的各种2-烷基和2-芳基取代的喹喔啉衍生物的一般不对称氢化反应。在温和的反应条件下,可以以高收率和高达95%的良好至优异的对映选择性获得相应的生物学上相关的2-取代-1,2,3,4-四氢喹喔啉单元。催化剂比为S / C = 1000且以克为单位,Ir-二氟膦配合物的催化活性得以保持,并显示出其潜在价值。最后,我们证明了我们的方法在化合物(S)-9的合成中的应用,该化合物是胆固醇酯转移蛋白(CETP)的抑制剂。
Asymmetric Transfer Hydrogenation of 2-Substituted Quinoxalines with Regenerable Dihydrophenanthridine
作者:Zaiqi Han、Xiangqing Feng、Haifeng Du
DOI:10.1021/acs.joc.3c02954
日期:2024.3.1
represents one of the most efficient approaches for the synthesis of optically active tetrahyroquinoxalines. In this paper, we demonstrate a metal-free asymmetric transfer hydrogenation of 2-substituted quinoxalines with regenerable dihydrophenanthridine under H2 using a combination of chiral phosphoric acid and achiral borane as catalysts. A wide range of optically active 2-substituted tetrahydroquinoxalines
喹喔啉的不对称氢化是合成光学活性四氢喹喔啉的最有效方法之一。在本文中,我们展示了在H 2下,使用手性磷酸和非手性硼烷作为催化剂,2-取代的喹喔啉与可再生二氢菲啶的无金属不对称转移氢化。以≤98% ee 的高产率生产了多种光学活性 2-取代四氢喹喔啉。
Iridium‐Difluorphos‐Catalyzed Asymmetric Hydrogenation of 2‐Alkyl‐ and 2‐Aryl‐Substituted Quinoxalines: A General and Efficient Route into Tetrahydroquinoxalines
AbstractA highly efficient and general iridium‐difluorphos‐catalyzed asymmetric hydrogenation of diverse 2‐alkyl‐ and 2‐aryl‐substituted quinoxalines into biologically and pharmaceutically relevant 2‐substituted‐1,2,3,4‐tetrahydroquinoxaline units has been developed. High isolated yields and excellent enantioselectivities of up to 95% for 2‐alkyl‐substituted quinoxalines and of up to 94% for 2‐aryl‐substituted quinoxalines were obtained.