76154-10-4Relevant academic research and scientific papers
Chiral imine-containing quinoline oxazoline compound and metal complex thereof as well as preparation method and application
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Paragraph 0150-0155, (2022/01/12)
The invention discloses a chiral imine-containing quinoline oxazoline compound which is high in optical purity and has a structural formula as shown in a formula (1), and discloses a preparation method of the chiral imine-containing quinoline oxazoline compound. The invention also discloses a metal complex obtained by complexing the chiral imine-containing quinoline oxazoline compound and a transition metal salt, wherein the metal complex is shown as a formula (6). The synthetic route is efficient, and the total yield of two steps can reach 85%. The metal complex of the chiral imine-containing quinoline oxazoline compound can be used as a catalyst to catalyze hydrosilylation or hydroboration on a carbon-carbon or carbon heteroatom double bond, and is especially suitable for preparing chiral organic compounds with high regioselectivity and optical selectivity.
Chiral N-heterocyclic carbene-iridium complexes for asymmetric reduction of prochiral ketimines
Kathuria, Lakshay,Samuelson, Ashoka G.
, (2020/12/28)
Enantioselective reduction of imines to the corresponding chiral secondary amines has been studied using a series of chiral half-sandwich iridium complexes. Chiral N-heterocyclic carbene (NHC) ligands in these complexes were synthesized from readily available, naturally occurring amino acids. Inexpensive phenylsilane was used as a convenient hydrogen donor. Under the optimized conditions, Ir-NHC complexes could reduce ketimines in good yields, albeit with moderate enantiomeric excess (ee). The phenylglycine derived chiral NHC was shown to give the best Ir catalyst and it also gave the maximum ee compared to catalysts prepared from other NHCs in this series. The opposite enantiomer of the reduction product was always obtained while using the Ir complex bearing a valine based NHC. The yields were consistently high with a variety of imine substrates having different steric and electronic demands.
Ruthenium N-Heterocyclic Carbene Complexes for Chemoselective Reduction of Imines and Reductive Amination of Aldehydes and Ketones
Kathuria, Lakshay,Samuelson, Ashoka G.
supporting information, (2020/06/17)
Chemoselective reduction of imines to secondary amines is catalyzed efficiently by tethered and untethered, half-sandwich ruthenium N-heterocyclic carbene (NHC) complexes at room temperature. The untethered Ru-NHC complexes are more efficient as catalysts for the reduction of aldimines and ketimines than the tethered complexes. Using the best untethered complex as a catalyst, electronic and steric demands on the reaction was probed using a series of imines. Chemoselectivity of the catalyst towards imine reduction was tested by performing inter and intramolecular competitive reactions in a variety of ways. The catalyst exhibits a very high TON and TOF under anaerobic conditions.
Chemoselective Reduction of Imines Catalyzed by Ruthenium(II) Half-Sandwich Complexes: A Mechanistic Study
Reshi, Noor U. Din,Kathuria, Lakshay,Samuelson, Ashoka G.
, p. 2947 - 2955 (2019/06/27)
Ruthenium half-sandwich complexes ligated to chiral 2-oxazolidinethiones or 2-thiozolidinethiones in the reduction of N-benzylideneaniline using silyl hydrides as reductants has been examined. The chemoselective reduction of imines takes place under mild conditions to afford the corresponding amines in nearly quantitative yield. Mechanistic studies indicate that dissociation of the ancillary ligands generate the active catalyst in all the complexes studied, which is the same species generated by [Ru(p-cymene)(Cl)2]2 under the reaction conditions. This results in the formation of a single catalytic species irrespective of the starting half-sandwich complex. Detailed mechanistic studies involving trapping of intermediates, in situ studies using mass spectrometry and NMR spectroscopy were carried out using the active catalyst generated by [Ru(p-cymene)(Cl)2]2. The mechanism of the reaction is dependent on the number of the hydrogen atoms in the reducing silane. The reaction proceeds via Gade-Hoffman pathway or Zheng-Chan pathway when a dihydro or trihydrosilane is the reductant. However, the use of a monohydrosilane, leads to longer reaction times presumably due to a change in the reaction pathway.
Synthesis and application of axially chiral biscarbolines with functional N-O and sulfone for 1,2-transfer hydrogenations of ketimines
Xing, Yongfei,Wu, Shijie,Dong, Mengxian,Wang, Jie,Liu, Li,Zhu, Huajie
supporting information, (2019/08/08)
A series of axially chiral biscarboline-based sulfones were synthesized from L-tryptophane and applied for enantioselective 1,2-transfer hydrogenations of ketimines using trichlorosilane. The catalyst 4e, which had a tertiary butyl group, exhibited a good conversion and high enantioselectivities up to 96%ee in the series of reactions.
Improving C=N bond reductions with (Cyclopentadienone)iron complexes: Scope and limitations
Cettolin, Mattia,Bai, Xishan,Lübken, Dennis,Gatti, Marco,Facchini, Sofia Vailati,Piarulli, Umberto,Pignataro, Luca,Gennari, Cesare
supporting information, p. 647 - 654 (2018/10/24)
Herein, we broaden the application scope of (cyclo-pentadienone)iron complexes 1 in C=N bond reduction. The catalytic scope of pre-catalyst 1b, which is more active than the “Kn?lker complex” (1a) and other members of its family, has been expanded to the catalytic transfer hydrogenation (CTH) of a wider range of aldimines and ketimines, either pre-isolated or generated in situ. The kinetics of 1b-promoted CTH of ketimine S1 were assessed, showing a pseudo-first order profile, with TOF = 6.07 h–1 at 50 % conversion. Moreover, the chiral complex 1c and its analog 1d were employed in the enantioselective reduction of ketimines and reductive amination of ketones, giving fair to good yields and moderate enantioselectivity.
Rhodium-Catalyzed C=N Bond Formation through a Rebound Hydrolysis Mechanism and Application in β-Lactam Synthesis
Chen, Long,Zhang, Linxing,Shao, Ying,Xu, Guangyang,Zhang, Xinhao,Tang, Shengbiao,Sun, Jiangtao
supporting information, p. 4124 - 4127 (2019/06/08)
A rhodium-catalyzed reaction of N-hydroxyanilines with diazo compounds to produce α-imino esters was developed. Distinct from the commonly accepted 1,2-H transfer for normal X-H insertion reactions, density functional theory calculations indicate that this transformation proceeds via a novel rebound hydrolysis mechanism. Furthermore, a three-component reaction was explored to synthesize highly functionalized β-lactams in good yields and diastereoselectivities.
An efficient proline-based homogeneous organocatalyst with recyclability
Li, Qiang,Li, Yuan,Wang, Jingdong,Lin, Yingjie,Wei, Zhonglin,Duan, Haifeng,Yang, Qingbiao,Bai, Fuquan,Li, Yaoxian
supporting information, p. 827 - 831 (2018/02/03)
In this work, a homogeneous organocatalyst was developed for the asymmetric reduction of imines. This catalyst could be separated by cyclodextrin-modified Fe3O4@SiO2 magnetic nanoparticles and then released back into a fre
Transition-Metal-Free Addition of Acetylenes to Ketimines: the First Base-Catalyzed Ethynylation of the C=N Bond
Bidusenko, Ivan A.,Schmidt, Elena Yu.,Ushakov, Igor A.,Trofimov, Boris A.
supporting information, p. 4845 - 4849 (2018/09/14)
A one-pot transition metal-free synthesis of propargylamines in good to excellent yield from ketone-derived imines and aryl- and hetarylacetylenes in the presence of KOBut/DMSO superbase system (40 °C, 10 min) has been developed. The reaction i
A green and efficient hydration of alkynes catalyzed by hierarchically porous poly(ionic liquid)s solid strong acids
Tao, Duan-Jian,Liu, Fujian,Wang, Lin,Jiang, Lilong
, p. 56 - 63 (2018/07/29)
The catalytic conversion of alkynes into ketones via hydration has received considerable attention, because the ketones are very important intermediates in the chemical and pharmaceutical industries. The hydration of alkynes was usually performed with rather complicated processes in presence of liquid acids or highly toxic metal catalysts. We report here a novel metal free and efficient route to conversion of alkynes into ketones catalyzed by hierarchically porous poly(ionic liquid)s solid strong acids, which were synthesized from one-step, template-free copolymerization of divinylbenzene (DVB) with nitrogen containing monomers under solvothermal condition, further by post grafting with strong acid ionic liquid groups. The porous poly(ionic liquid)s solid acids have large BET surface areas, hierarchical nanopores and enhanced acid strength. A variety of alkynes could be effectively transformed into ketones catalyzed by the synthesized porous poly(ionic liquid)s solid acids under green and mild conditions, which were much better than those of Amberlyst 15, phosphotungstic acid and sulfuric acid. Furthermore, the porous poly(ionic liquid)s solid acids also show excellent activities and good reusability in direct hydroamination of amines with phenylacetylene. This work largely expands the wide applications of porous poly(ionic liquid)s solid strong acids in hydration and hydroamination, which develops a green, efficient and cost effective approach for conversion of low cost alkynes into high-value added ketones.
