76201-90-6Relevant academic research and scientific papers
Asymmetric Transfer Hydrogenation of Unhindered and Non-Electron-Rich 1-Aryl Dihydroisoquinolines with High Enantioselectivity
Barrios-Rivera, Jonathan,Xu, Yingjian,Wills, Martin
supporting information, p. 6283 - 6287 (2020/09/02)
The use of arene/Ru/TsDPEN catalysts bearing a heterocyclic group on the TsDPEN in the asymmetric transfer hydrogenation (ATH) of dihydroisoquinolines (DHIQs) containing meta- or para-substituted aromatic groups at the 1-position results in the formation of products of high enantiomeric excess. Previously, only 1-(ortho-substituted)aryl DHIQs, or with an electron-rich fused ring gave products with high enantioselectivity; therefore, this approach solves a long-standing challenge for imine ATH.
Josiphos-Type Binaphane Ligands for Iridium-Catalyzed Enantioselective Hydrogenation of 1-Aryl-Substituted Dihydroisoquinolines
Nie, Huifang,Zhu, Yupu,Hu, Xiaomu,Wei, Zhao,Yao, Lin,Zhou, Gang,Wang, Pingan,Jiang, Ru,Zhang, Shengyong
supporting information, p. 8641 - 8645 (2019/10/17)
Convenient synthesis and useful application of a series of Josiphos-type binaphane ligands were described. The iridium complexes of these chiral diphosphines displayed excellent enantioselectivity and good reactivity in the asymmetric hydrogenation of challenging 1-aryl-substituted dihydroisoquinoline substrates (full conversions, up to >99% ee, 4000 TON). The use of 40% HBr (aqueous solution) as an additive dramatically improved the asymmetric induction of these catalysts. This transformation provided a highly efficient and enantioselective access to chiral 1-aryl-substituted tetrahydroisoquinolines, which were of great importance and common in natural products and biologically active molecules.
Mechanistic Studies on Bioinspired Aerobic C-H Oxidation of Amines with an ortho-Quinone Catalyst
Zhang, Ruipu,Qin, Yan,Zhang, Long,Luo, Sanzhong
supporting information, p. 2542 - 2555 (2019/03/08)
We report herein our mechanistic studies of the ortho-quinone-catalyzed aerobic oxidation of primary, secondary, and tertiary amines. Two different catalytic pathways were discovered for the reductive half reactions: for primary amines, the reaction was found to proceed via a transamination pathway, while the reactions with secondary amines and tertiary amines proceeded via hydride transfer. We also found that the amine substrates could significantly promote the regeneration of the ortho-quinone catalyst in the oxidative half reaction, in which a proton transfer occurs between the amine substrates and catechol derivatives (the reduced form of the ortho-quinone catalyst).
Method for solvent accelerated selective dehydrogenation of tetrahydroisoquinoline type compound
-
Paragraph 0039; 0040; 0041; 0042; 0043, (2017/07/22)
The invention discloses a method for synthesizing 1-substituted-3,4-dihydroisoquinoline through the solvent accelerated selective partial dehydrogenation of a 1-substituted-1,2,3,4-tetrahydroisoquinoline compound. For a simple and easily obtained cyclic amine type compound such as a tetrahydroisoquinoline compound, a corresponding imine compound can be obtained through selective dehydrogenation; the conversion ratio of the cyclic amine type compound is higher; further, the proportion of a partially dehydrogenated product to a fully dehydrogenated product is more than 20 to 1. The method is simple and convenient to operate, is practical, easy and feasible, and is mild in reaction condition; the actual cost is greatly reduced. In addition, a method for synthesizing 3,4-dihydroisoquinoline through the direct dehydrogenation of tetrahydroisoquinoline has the advantages of atom economy and environmental friendliness.
One-Pot N-Deprotection and Catalytic Intramolecular Asymmetric Reductive Amination for the Synthesis of Tetrahydroisoquinolines
Zhou, Huan,Liu, Yuan,Yang, Suhua,Zhou, Le,Chang, Mingxin
, p. 2725 - 2729 (2017/02/26)
A one-pot N-Boc deprotection and catalytic intramolecular reductive amination protocol for the preparation of enantiomerically pure tetrahydroisoquinoline alkaloids is described. The iodine-bridged dimeric iridium complexes displayed superb stereoselectivity to give tetrahydroisoquinolines, including several key pharmaceutical drug intermediates, in excellent yields under mild reaction conditions. Three additives played important roles in this reaction: Titanium(IV) isopropoxide and molecular iodine accelerated the transformation of the intermediate imine to the tetrahydroisoquinoline product; p-toluenesulfonic acid contributed to the stereocontrol.
Cerium Chloride Catalyzed, 2-Iodoxybenzoic Acid Mediated Oxidative Dehydrogenation of Multiple Heterocycles at Room Temperature
Hati, Santanu,Sen, Subhabrata
supporting information, p. 1277 - 1280 (2017/03/17)
Catalytic cerium chloride was found to activate 2-iodoxybenzoic acid (IBX) for the oxidative dehydrogenation of tetrahydroisoquinolines, tetrahydro-β-carbolines, and thiazolidines to their dehydrogenated and aromatic forms at room temperature in moderate to excellent yields. The robustness of the protocol was demonstrated by scaling up the reactions to multigram quantities.
Solvent-promoted highly selective dehydrogenation of tetrahydroisoquinolines without catalyst and hydrogen acceptor
Feng, Guang-Shou,Ji, Yue,Liu, Hui-Fang,Shi, Lei,Zhou, Yong-Gui
supporting information, p. 747 - 749 (2016/02/05)
An unusual solvent DMF-promoted dehydrogenation of 1-substituted 1,2,3,4-tetrahydroisoquinolines to synthesize cyclic imines is described. This environmentally friendly reaction features no requirement of any metal catalysts, oxidants, or hydrogen acceptors. A wide range of structurally varied 3,4-dihydroisoquinolines can be obtained with good yields and excellent chemoselectivities.
Enantioselective Synthesis of 1-Aryl-Substituted Tetrahydroisoquinolines Through Ru-Catalyzed Asymmetric Transfer Hydrogenation
Perez, Marc,Wu, Zi,Scalone, Michelangelo,Ayad, Tahar,Ratovelomanana-Vidal, Virginie
, p. 6503 - 6514 (2015/10/19)
A convenient and general asymmetric transfer hydrogenation of a wide array of 1-aryl-3,4-dihydroisoquinoline derivatives using a [RuIICl(η6-benzene)TsDPEN] complex in combination with a 5:2 HCOOH-Et3N azeotropic mixture as a hydrogen source was developed. Under mild reaction conditions, the described catalytic transformation secured a practical synthetic access to the corresponding valuable chiral 1-aryltetrahydroisoquinoline units with high atom economy, a broad substrate scope, high isolated yields (up to 97%) and good to excellent enantioselectivities (up to 99% ee). It was found that the stereochemical outcome of the reaction was strongly influenced by both the structure of the catalyst and the substituents present on the substrate. The synthetic utility of the present protocol has been demonstrated through the asymmetric synthesis of several biologically important alkaloids including the antiepileptic drug agent 1c, as well as (-)-nor-cryptostyline alkaloids I and II.
Cooperative dehydrogenation of N-heterocycles using a carbon nanotube-rhodium nanohybrid
Jawale, Dhanaji V.,Gravel, Edmond,Shah, Nimesh,Dauvois, Vincent,Li, Haiyan,Namboothiri, Irishi N.N.,Doris, Eric
supporting information, p. 7039 - 7042 (2015/05/05)
Rhodium nanoparticles were anchored on carbon nanotubes and the resulting nanohybrid was studied as co-catalyst, along with tert-butylcatechol, for the dehydrogenation of various N-heterocycles. The co-catalytic system operates in high yields, under the mildest conditions reported so far, and can be applied to a wide variety of secondary amine-containing scaffolds.
Bioinspired aerobic oxidation of secondary amines and nitrogen heterocycles with a bifunctional quinone catalyst
Wendlandt, Alison E.,Stahl, Shannon S.
, p. 506 - 512 (2014/01/23)
Copper amine oxidases are a family of enzymes with quinone cofactors that oxidize primary amines to aldehydes. The native mechanism proceeds via an iminoquinone intermediate that promotes high selectivity for reactions with primary amines, thereby constraining the scope of potential biomimetic synthetic applications. Here we report a novel bioinspired quinone catalyst system consisting of 1,10-phenanthroline-5,6-dione/ZnI2 that bypasses these constraints via an abiological pathway involving a hemiaminal intermediate. Efficient aerobic dehydrogenation of non-native secondary amine substrates, including pharmaceutically relevant nitrogen heterocycles, is demonstrated. The ZnI2 cocatalyst activates the quinone toward amine oxidation and provides a source of iodide, which plays an important redox-mediator role to promote aerobic catalytic turnover. These findings provide a valuable foundation for broader development of aerobic oxidation reactions employing quinone-based catalysts.
