- Asymmetric Transfer Hydrogenation of Unhindered and Non-Electron-Rich 1-Aryl Dihydroisoquinolines with High Enantioselectivity
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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.
- Barrios-Rivera, Jonathan,Xu, Yingjian,Wills, Martin
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p. 6283 - 6287
(2020/09/02)
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- Josiphos-Type Binaphane Ligands for Iridium-Catalyzed Enantioselective Hydrogenation of 1-Aryl-Substituted Dihydroisoquinolines
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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.
- Nie, Huifang,Zhu, Yupu,Hu, Xiaomu,Wei, Zhao,Yao, Lin,Zhou, Gang,Wang, Pingan,Jiang, Ru,Zhang, Shengyong
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p. 8641 - 8645
(2019/10/17)
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- One-Pot N-Deprotection and Catalytic Intramolecular Asymmetric Reductive Amination for the Synthesis of Tetrahydroisoquinolines
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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.
- Zhou, Huan,Liu, Yuan,Yang, Suhua,Zhou, Le,Chang, Mingxin
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p. 2725 - 2729
(2017/02/26)
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- Enantioselective Synthesis of 1-Aryl-Substituted Tetrahydroisoquinolines Through Ru-Catalyzed Asymmetric Transfer Hydrogenation
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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.
- Perez, Marc,Wu, Zi,Scalone, Michelangelo,Ayad, Tahar,Ratovelomanana-Vidal, Virginie
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p. 6503 - 6514
(2015/10/19)
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- New synthetic approach for the preparation of 1-Aryl-3,4-dihydroisoquinolines by liebeskind-srogl reaction
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An efficient synthetic methodology has been developed to construct 1-aryl-3,4-dihydroisoquinoline derivatives. The reaction was performed under neutral conditions by a palladium-catalyzed desulfitative carbon-carbon cross-coupling protocol.
- ábrányi-Balogh, Péter,Slégel, Péter,Volk, Balázs,Pongó, László,Milen, Mátyás
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p. 2574 - 2578
(2015/01/09)
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- Oxidative C-H functionalization: A novel strategy for the acetoxylation/alkoxylation of arenes tethered to 3,4-dihydroisoquinolines
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1-Aryl-3,4-dihydroisoquinolines undergo smooth acetoxylation/alkoxylation in the presence of 5 mol % Pd(OAc)2 and a stoichiometric amount of PhI(OAc)2 by means of C-H activation to produce the corresponding acetoxy- and alkoxy-1-aryl-3,4-dihydroisoquinoline derivatives respectively in good yields with high regioselectivity. It is a first example on oxidative functionalization of arenes tethered to dihydroisoquinoline moiety via the C-H activation.
- Subba Reddy,Umadevi,Narasimhulu,Yadav
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p. 6091 - 6094
(2012/11/07)
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- A highly efficient and enantioselective access to tetrahydroisoquinoline alkaloids: Asymmetric hydrogenation with an iridium catalyst
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Efficient and enantioselective: Using the iodine-bridged dimeric iridium complex [{Ir(H)[(S,S)-(f)-binaphane]}2(μ-I)3] +I- (1) a wide range of tetrahydroisoquinoline alkaloids, including the substructure of the pharmaceutical drug solifenacin, were obtained with excellent enantioselectivities and high turnover numbers (see scheme). Copyright
- Chang, Mingxin,Li, Wei,Zhang, Xumu
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p. 10679 - 10681
(2011/12/05)
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