Single-Operation Deracemization of 3H-Indolines and Tetrahydroquinolines Enabled by Phase Separation
摘要:
The single-operation deracemization of 3H indolines and tetrahydroquinolines is described. An asymmetric redox approach was employed, in which a phosphoric acid catalyst, oxidant, and reductant are present in the reaction mixture. The simultaneous presence of both oxidant and reductant was enabled by phase separation and resulted in the isolation of highly enantioenriched starting materials in high yields.
Chiral phosphoric acid catalyzed oxidative kinetic resolution of cyclic secondary amine derivatives including tetrahydroquinolines by hydrogen transfer to imines
Asymmetric Synthesis of Hydroquinolines with α,α‐Disubstitution through Organocatalyzed Kinetic Resolution
作者:Yunrong Chen、Chaofan Zhu、Zheng Guo、Wei Liu、Xiaoyu Yang
DOI:10.1002/anie.202015008
日期:2021.3
The first kinetic resolution of hydroquinoline derivatives with α,α‐disubstitution has been achieved through asymmetric remote aminations with azodicarboxylates enabled by chiral phosphoric acid catalysis. Mechanistic studies suggest a monomeric catalyst pathway proceeding through rate‐ and enantio‐determining electrophilic attack promoted by a network of attractive non‐covalent interactions between
AbstractThis study reports on the thiourea dioxide catalyzed transferhydrogenation of diverse C=N–containing heterocyclic compounds with Hantzsch ester as the hydrogen source. With this cost effective and readily available catalyst, a wide range of 2-substituted quinolines, 3-substituted-2H-1,4-benzoxazines and 3-substituted-2H-1,4-benzothiazines were efficiently reduced to the corresponding tetrahydroquinolines
A simple and readily available cyclopentadiene-based Brønstedacid was employed to catalyze the transferhydrogenation of 2-substituted quinolines using Hantzsch ester as the hydrogen source. This conceptually new designed organocatalyst demonstrates remarkably high efficiency for this transformation and a variety of substituted 1,2,3,4-tetrahydroquinoline derivatives were afforded in excellent yields
Interlockedmolecules, such as catenanes, rotaxanes, and molecular knots, have become interesting candidates for the development of sophisticated chemical catalysts. Herein, we report the first application of a catenane-based catalyst in asymmetricorganocatalysis, revealing that the catenated catalyst shows dramatically increased stereoselectivities (up to 98 % ee) in comparison to its non-interlocked
S-Benzyl-N,N'-diphenyl substituted isothiouronium iodide as a highly efficient organocatalyst for transfer hydrogenation of 2-substituted quinolines
作者:Sungmin Kang、Taek Hyeon Kim
DOI:10.1016/j.tetlet.2021.153450
日期:2021.11
prepared from thiourea was first employed to catalyze the transfer hydrogenation of various 2-alkyl and arylquinolines with Hantzsch ester as the hydrogen source. This metal-free catalyzed reduction of 2-substitutedquinoline efficiently rendered good to excellent yields of tetrahydroquinolines under mild conditions with a small amount of catalyst (5 mol%).