开发了 Ir 催化的喹啉不对称氢化反应,通过调节反应溶剂(甲苯/二恶烷:产率高达 99%,98% ee),可以分别以高产率和良好的对映选择性轻松获得手性四氢喹啉衍生物的两种对映异构体( R ),TON = 680;EtOH:高达 99% 的产率,94% ee ( S ),TON = 1680)。它为手性四氢喹啉的对映发散合成提供了一种有效且简单的合成策略,并且在这两个反应体系中,克级不对称加氢反应在低催化剂负载的情况下顺利进行。一系列氘标记实验、对照实验和1进行了H NMR和电喷雾电离-质谱实验,并在这些有用观察的基础上揭示了合理和可能的反应过程。
Unprecedented Halide Dependence on Catalytic Asymmetric Hydrogenation of 2-Aryl- and 2-Alkyl-Substituted Quinolinium Salts by Using Ir Complexes with Difluorphos and Halide Ligands
the key to achieving high catalytic activity and enantioselectivity on asymmetric hydrogenation of 2‐aryl‐ and 2‐alkyl‐substituted quinolinium salts. The reaction was catalyzed by a cationic dinuclear iridium(III) complex with difluorphos and chloride or bromide ligands and gave the corresponding 2‐substituted 1,2,3,4‐tetrahydroquinolines in high enantioselectivities (up to 95 % ee; see scheme, difluorphos=[(4
synthesis of chiral tetrahydroquinoline derivatives with excellent enantioselectivities and high yields has been developed through one‐pot cascade biomimetic reduction. The detailed reaction pathway includes the acid‐catalyzed and ruthenium‐catalyzedformation of aromatic quinoline intermediates and biomimetic asymmetric reduction.
Asymmetric Reduction of Quinolines: A Competition between Enantioselective Transfer Hydrogenation and Racemic Borane Catalysis
作者:Bochao Gao、Zaiqi Han、Wei Meng、Xiangqing Feng、Haifeng Du
DOI:10.1021/acs.joc.2c02905
日期:2023.3.3
A chiral phosphoric acid catalyzed asymmetrictransferhydrogenation of quinolines with regenerable dihydrophenanthridine derived by a borane-catalyzed hydrogenation of phenanthridine under H2 has been successfully realized. Despite the competition of a racemic hydrogenation pathway, a variety of tetrahydroquinolines were furnished in high yields with up to 91% ee.
已成功实现了由硼烷催化氢化菲啶在H 2 下衍生的手性磷酸催化喹啉与可再生二氢菲啶的不对称转移氢化反应。尽管存在外消旋氢化途径的竞争,但仍以高达 91% ee 的高产率提供了多种四氢喹啉。