33770-43-3Relevant academic research and scientific papers
Asymmetric Transfer Hydrogenation of Imines in Water by Varying the Ratio of Formic Acid to Triethylamine
Shende, Vaishali S.,Deshpande, Sudhindra H.,Shingote, Savita K.,Joseph, Anu,Kelkar, Ashutosh A.
, p. 2878 - 2881 (2015)
Asymmetric transfer hydrogenation (ATH) of imines has been performed with variation in formic acid (F) and triethylamine (T) molar ratios in water. The F/T ratio is shown to affect both the reduction rate and enantioselectivity, with the optimum ratio being 1.1 in the ATH of imines with the Rh-(1S,2S)-TsDPEN catalyst. Use of methanol as a cosolvent enhanced reduction activity. A variety of imine substrates have been reduced, affording high yields (94-98%) and good to excellent enantioselectivities (89-98%). In comparison with the common azeotropic F-T system, the reduction with 1.1/1 F/T is faster.
Asymmetric Transfer Hydrogenation of Unhindered and Non-Electron-Rich 1-Aryl Dihydroisoquinolines with High Enantioselectivity
Barrios-Rivera, Jonathan,Xu, Yingjian,Wills, Martin
, 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.
Biosynthesis of plant tetrahydroisoquinoline alkaloids through an imine reductase route
Yang, Lu,Zhu, Jinmei,Sun, Chenghai,Deng, Zixin,Qu, Xudong
, p. 364 - 371 (2020/01/21)
Herein, we report a biocatalytic approach to synthesize plant tetrahydroisoquinoline alkaloids (THIQAs) from dihydroisoquinoline (DHIQ) precursors using imine reductases and N-methyltransferase (NMT). The imine reductase IR45 was engineered to significant
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
, 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.
Enantioselective Synthesis of 1-Aryl-Substituted Tetrahydroisoquinolines Through Ru-Catalyzed Asymmetric Transfer Hydrogenation
Perez, Marc,Wu, Zi,Scalone, Michelangelo,Ayad, Tahar,Ratovelomanana-Vidal, Virginie
supporting information, 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.
Asymmetric transfer hydrogenation of imines in water/methanol co-solvent system and mechanistic investigation by DFT study
Shende, Vaishali S.,Shingote, Savita K.,Deshpande, Sudhindra H.,Kuriakose, Nishamol,Vanka, Kumar,Kelkar, Ashutosh A.
, p. 46351 - 46356 (2015/02/19)
Asymmetric transfer hydrogenation of various cyclic imines proceeded efficiently with water/methanol co-solvent media in 20 min with excellent yields and enantioselectivities by employing Rh-TsDPEN catalyst and sodium formate as a hydrogen donor. The role
Efficient and Practical Syntheses of Enantiomerically Pure (S)-(-)-Norcryptostyline I, (S)-(-)-Norcryptostyline II, (R)-(+)-Salsolidine and (S)-(-)-Norlaudanosine via a Resolution-Racemization Method
Zhu, Ruiheng,Xu, Zhangli,Ding, Wei,Liu, Shiling,Shi, Xiaoxin,Lu, Xia
, p. 1039 - 1048 (2016/02/18)
Four racemic tetrahydroisoquinolines (RS)-(±)-1-4 were prepared from homoveratrylamine via amidation, Bischler-Napieralski reaction and the subsequent reduction. The enantiomerically pure tetrahydroisoquinolines (S)- (-)-norcryptostyline I [(S)-(-)-1], (S)-(-)-norcryptostyline II [(S)-(-)-2], (R)-(+)-salsolidine [(R)-(+)-3] and (S)-(-)-norlaudanosine [(S)-(-)-4] were then obtained in 45%, 40%, 41% and 38% yields, respectively, via resolution of the racemic compounds (RS)-(±)-1-4 with half equivalent of chiral acids. In addition, the enantiomerically enriched compounds (R)-(+)-1, (R)-(+)-2, (S)-(-)-3 and (R)-(+)-4 from the mother liquors were efficiently racemized via a one-pot redox method in almost quantitative yields.
A highly efficient and enantioselective access to tetrahydroisoquinoline alkaloids: Asymmetric hydrogenation with an iridium catalyst
Chang, Mingxin,Li, Wei,Zhang, Xumu
, p. 10679 - 10681 (2011/12/05)
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
A general methodology for the enantioselective synthesis of 1-substituted tetrahydroisoquinoline alkaloids
Amat, Mercedes,Elias, Viviane,Llor, Nuria,Subrizi, Fabiana,Molins, Elies,Bosch, Joan
experimental part, p. 4017 - 4026 (2010/10/02)
Starting from tricyclic lactam 2, which is easily accessible by cyclocondensation of δ-oxoester 1 with (R)-phenylglycinol, a three-step synthetic route to enantiopure 1-substituted tetrahydroisoquinolines, including 1-alkyl-, 1-aryl-, and 1-benzyltetrahydroisoquinoline alkaloids, as well as the tricyclic alkaloid (-)-crispine A, has been developed. The key step is a stereoselective α-amidoalkylation reaction using the appropriate Grignard reagent.
