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1.
A simple and scalable procedure for the preparation of chiral ligands 1 and 2 from trans‐1,2‐diaminocyclohexane and 2‐picolinic acid is described. 相似文献
2.
Qi Zhang Yonghai Hui Xin Zhou Lili Lin Xiaohua Liu Xiaoming Feng 《Advanced Synthesis \u0026amp; Catalysis》2010,352(6):976-980
The asymmetric three‐component vinylogous Mannich reaction of an acyclic silyl dienol ester, an aldehyde and 2‐aminophenol was accomplished using a chiral N,N′‐dioxide‐scandium(III) complex as the catalyst. A variety of aldehydes were found to be suitable substrates for the reaction and the desired δ‐amino‐α,β‐unsaturated esters were obtained in 90–99% yields with good to excellent enantioselectivities (up to >99% ee) and complete regioselectivities. Moreover, the simple experimental procedures were air‐tolerant and convenient. The present catalytic process provides the potential for large‐scale syntheses of the chiral δ‐amino‐α,β‐unsaturated esters. 相似文献
3.
T. Zimmermann G. W. Fischer J. Teller H. Dehne B. Olk 《Advanced Synthesis \u0026amp; Catalysis》1990,332(5):723-730
Substituted N,N′-Bis(thiazol-2-yl)-diaminoalkanes from α-Thiocyanato-acetophenones and N,N′-Dialkyl-diaminoalkanes α-Thiocyanato-acetophenones 1 react with N,N′-dialkyl-diaminoalkanes 2 in the presence of an appropriate weak acid (acetic acid, propionic acid, benzoic acid) to give the hitherto unknown N,N′-dialkyl-N,N′-bis(4-aryl-thiazol-2-yl)-diaminoalkanes 3 . As reaction medium aliphatic alcohols (ethanol, methanol), halogenated hydrocarbons (methylene chloride, chloroform, carbon tetrachloride) or dipolar-aprotic solvents (acetonitrile, dimethylformamide) can be used. - I.r., u.v., n.m.r. and mass spectroscopic data of the novel bisthiazoles 3 are reported. 相似文献
4.
Xiao Huang Jinglun Huang Yuehong Wen Xiaoming Feng 《Advanced Synthesis \u0026amp; Catalysis》2006,348(18):2579-2584
A novel bifunctional N,N′‐dioxide derived from L ‐prolinamide was employed to catalyze the enantioselective Strecker reaction of a range of N‐tosyl ketoimines, and an effective additive was used to improve the reactivity (up to 99 % yield) as well as the enantioselectivity (up to 91 % ee). In addition, a rational transition state was proposed to elucidate the origin of chiral induction in which an S‐adduct was produced. 相似文献
5.
Yangyang Chu Xiaoyu Hao Lili Lin Weiliang Chen Wei Li Fei Tan Xiaohua Liu Xiaoming Feng 《Advanced Synthesis \u0026amp; Catalysis》2014,356(10):2214-2218
The catalytic asymmetric epoxidation of 2‐arylidene‐1,3‐diketones using aqueous 30% H2O2 as oxidant has been successfully realized by a N,N′‐dioxide–scandium(III) triflate [Sc(OTf)3] complex, giving the corresponding products in moderate to good yields (up to 85%) with excellent enantioselectivities (up to 99% ee) under mild reaction conditions without extra additives.
6.
N,N′-Bis(2-nitro-benzodifuroxanyl)-1,3,5-trinitro-2,6-diaminobenzene has been synthesized from 1,3-diaminobenzene and trinitrotrichlorobenzene. The molecular structure of this compound has been determined by elemental analysis, IR, 1HNMR, and MS spectroscopies. 相似文献
7.
MnIII(J-salen)Cl (Jacobsen catalyst) with J-salen=N,N′-bis(3,5-di-tert.-butylsalicylidene)-1,2-diaminocyclohexane dianion in CHCl3 is photooxidized by the solvent to a MnIV(J-salen) complex, presumably MnIV(J-salen)Cl2, with φ=0.002 at λirr=333 nm. 相似文献
8.
9.
Tengfei Kang Zhen Wang Lili Lin Yuting Liao Yuhang Zhou Xiaohua Liu Xiaoming Feng 《Advanced Synthesis \u0026amp; Catalysis》2015,357(9):2045-2049
An N,N′‐dioxide/zinc bis(trifluoromethylsulfonyl)imide complex has been developed as an efficient catalyst for the highly enantioselective Diels–Alder reaction of cyclopentadiene with alkynones. Various 2‐acyl substituted norbornadiene derivatives were obtained in moderate to high yields (up to 99 %) with good enantiomeric excesses (up to 95 %).
10.
Radim Hrdina Irena Valterov Jana Hoda
ov Ivana Císaov Martin Kotora 《Advanced Synthesis \u0026amp; Catalysis》2007,349(6):822-826
The [2+2+2] cyclotrimerization of 1‐isoquinolinyl‐1,7‐octadiyne with benzonitrile catalyzed by CpCo(CO)2 opened a new pathway for a synthesis of unsymmetrical axially chiral bipyridine N,N′‐dioxides. The N,N′‐dioxide 3a was found to be highly catalytically active and enantioselective for the asymmetric allylation of aldehydes with allyltrichlorosilane. The allylation took place with even 1 % of the catalyst with an enantioselectivity up to 87 % ee. 相似文献
11.
12.
The results of studies on effects of the amount and type of oxirane, amount of catalyst and water, and temperature on the course of reactions taking place in the system N,N,N′,N′,N″‐pentakis(hydroxymethyl)melamine (PHMM)–oxirane carried out in aqueous media are reported. Quantitative determination of the content of functional groups present in the system and of side products formed in reactions of oxirane with water, made it possible to analyze in detail the processes taking place in the system. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 824–836, 2000 相似文献
13.
Jacek Lubczak 《应用聚合物科学杂志》1997,65(13):2589-2602
The effects of the kind and amount of oxirane (propylene or ethylene oxide), the amount of triethylamine catalyst, and the temperature on the reaction with N,N,N′,N′,N′-pentakis (hydroxymethyl) melamine (PHMM) in DMSO solution were studied. The changes in the content of reactive groups in the reaction mixture and in the final product were analyzed. The oxirane addition was shown to be accompanied by the condensation of hydroxymethyl groups in the PHMM. Optimal conditions for the synthesis and the structural formula of the s-triazine ring containing polyetherols were established. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2589–2602, 1997 相似文献
14.
A novel tetrafunctional epoxy resin, namely N,N,N′N′-tetrakis(2,3-epoxypropyl)-4,4′-(1,4-phenylenedioxy)dianiline, has been synthesized. The curing kinetics has been studied by differential scanning calorimetry (DSC) using various amine curing agents. Thermal stabilities of the cured products have been investigated by thermogravimetric (TG) analyses. The overall activation energies for the curing reactions are observed to be in the range 63.6–196.7 kJ·mol–1. The cured products have good thermal stability. 相似文献
15.
Xiying Zhang Jianlin Zhang Lili Lin Haifeng Zheng Wangbin Wu Xiaohua Liu Xiaoming Feng 《Advanced Synthesis \u0026amp; Catalysis》2016,358(19):3021-3026
A highly efficient chiral N,N′‐dioxide‐zinc(II) complex catalytic system has been developed for the enantioselective aza‐Friedel–Crafts reaction of isatin‐derived ketimines with indoles. A series of enantiomerically enriched 3‐indolyl‐3‐aminooxindoles containing a tetrasubstituted stereocenter were obtained in up to 99% yield with up to 96% ee. Furthermore, control experiments provide a fundamental sight into the mechanism of the reaction.
16.
Pengfei Zhou Yunfei Cai Lili Lin Xiangjin Lian Yong Xia Xiaohua Liu Xiaoming Feng 《Advanced Synthesis \u0026amp; Catalysis》2015,357(4):695-700
A highly efficient chiral N,N′‐dioxide–nickel(II) complex system has been developed to catalyze the domino thia‐Michael/aldol reaction of 1,4‐dithiane‐2,5‐diol with 3‐alkenyloxindoles. A series of the desired spirocyclic oxindole‐fused tetrahydrothiophenes was obtained in good yields with excellent ee and dr (up to 97% yield, 98% ee, >19:1 dr). Besides, based on the X‐ray crystal structure of the catalyst as well as the absolute configuration of the product, a catalytic model was proposed to explain the stereocontrol process.
17.
Radim Hrdina Martin Dra
ínský Irena Valterov Jana Hoda
ov Ivana Císaov Martin Kotora 《Advanced Synthesis \u0026amp; Catalysis》2008,350(10):1449-1456
The [2+2+2] cyclotrimerization of 1,7,9,15‐hexadecatetrayne with nitriles catalyzed by dicarbonylcyclopentadienylcobalt(I) opened a new pathway for the synthesis of C2‐symmetrical bis(tetrahydroisoquinolines) that were used as starting material for the preparation of axially chiral bipyridine N,N′‐dioxides. The N,N′‐dioxides (1 mol%) were found to be highly catalytically active and enantioselective (up to 83% ee) for the asymmetric allylation of aldehydes with allyl(trichloro)silane in various solvents. In addition, a dramatic solvent effect was observed where the use of different solvents induced opposite chiralities of the product with the same enantiomer of the catalyst, e.g., 65% ee (S) in acetonitrile (MeCN) vs. 82% ee (R) in chlorobenzene. 相似文献
18.
N,N′-Bis(2,4-dinitrobenzofuroxanyl) -3,5-dinitro-2,6-diaminopyridine has been synthesized from 2,6-diaminopyridine and trinitrodichlorobenzene. For this compound, the structure has been determined by elemental analysis, IR,1HNMR and MS spectroscopies. 相似文献
19.
Xiaohu Zhao Mingsheng Xie Xiaohua Liu Yulong Zhang Xiao Xiao Lili Lin Xiaoming Feng 《Advanced Synthesis \u0026amp; Catalysis》2013,355(16):3253-3262
A highly effective aldol cyclization of α‐isothiocyanato imide to both β,γ‐unsaturated α‐keto esters and aryl‐substituted α‐keto esters has been developed. A chiral N,N′‐dioxide–yttrium triflate complex was used as the catalyst. A series of cyclic thiocarbamates bearing chiral quaternary stereocenters was synthesized in good to high yields, excellent diastereo‐ (up to 25:1 dr) and enantioselectivities (up to 99 % ee). In addition, the reaction could be carried out on a gram‐scale, and other functionalized derivatives are also conveniently transformed. Interestingly, a discrepancy of diastereoselection was observed between the reactions of β,γ‐unsaturated α‐keto esters and aryl‐substituted α‐keto esters. Moreover, a substrate dependency of non‐linear effects was observed in this reaction. On the basis of the experimental results and the absolute configuration of the products, possible catalytic models have been proposed to explain the origin of the asymmetric process.
20.
Elumalai Gnanamani Nagamalla Someshwar Jayakumar Sanjeevi Chinnasamy Ramaraj Ramanathan 《Advanced Synthesis \u0026amp; Catalysis》2014,356(10):2219-2223
The conformationally rigid chiral bicyclic skeleton tethered bipyridine N,N′‐dioxide (−)‐ 9 has been designed, synthesized and examined as an organocatalyst in the enantioselective ring opening of meso‐epoxides using tetrachlorosilane (SiCl4). The catalyst (−)‐ 9 is found to exhibit good enantioselectivity for substituted cis‐stilbene epoxides; whereas, the saturated cyclic meso‐epoxides display a moderate enantioselectivity. At −30 °C in chloroform, the catalyst (−)‐ 9 with 0.5 mol % loading generated the chlorohydrins in up to 97 % yield with up to 93 % ee. The possible creation of transient axial chiral environment around hypervalent silicon species due to the presence of conformationally rigid chiral bicyclic skeleton tethered bipyridine N,N′‐dioxide may be responsible for such enantioselectivity observed in the desymmetrization of meso‐epoxides.