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。
Quinoxaline-specific enantioselective sulfa-michael reaction catalyzed by chiral phosphoric acid
作者:Xiongfei Deng、Shiqi Zhang、Hesen Huang、Xin Cui、Zhuo Tang、Guangxun Li
DOI:10.1016/j.cclet.2023.108145
日期:2023.1
Highly enantioselective sulfa-Michael additions (SMA) between 2-alkenyl quinoxalines and aromatic thiols are accomplished using a low loading of chiralphosphoricacid catalyst (1 mol%). It was confirmed by an investigation of a lot of azaarenes that the two C=N units of quinoxalines are indispensable for controlling the reaction enantioselectivities. A series of non-terminal 2-alkenes substituted