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1.
There has been growing interest and research on new synthetic methods for thepreparation of well-defined polymers with chain-end functional groups[1~ 7] . Thesefunctional groups in polymers can participate in reversible ionic association;chainextension,branching,or crosslinking reactions with polyfunctional reagents;couplingand linking with reactive groups in other oligomer or polymer chains;and initiation ofpolymerization of other monomers[4~ 6] . The methodology of living anionic polyme-ri… 相似文献
2.
Asymmetric Conjugate Addition of Benzofuran‐2‐ones to Alkyl 2‐Phthalimidoacrylates: Modeling Structure–Stereoselectivity Relationships with Steric and Electronic Parameters
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Chen Yang En‐Ge Zhang Prof. Xin Li Prof. Jin‐Pei Cheng 《Angewandte Chemie (International ed. in English)》2016,55(22):6506-6510
A highly predictive model to correlate the steric and electronic parameters of tertiary amine thiourea catalysts with the stereoselectivity of Michael reactions of 3‐substituted benzofuranones and alkyl 2‐phthalimidoacrylates is described. As predicted, new 3,5‐bis(trifluoromethyl)benzyl‐ and methyl‐substituted tertiary amine thioureas turned out to be highly suitable catalysts for this reaction and enabled the synthesis of enantioenriched α‐amino acid derivatives with 1,3‐nonadjacent stereogenic centers. 相似文献
3.
Lital Tuchman‐Shukron Prof. Dr. Scott J. Miller Prof. Dr. Moshe Portnoy 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(8):2290-2296
Introduction of an L ‐amino acid as a spacer and a urea‐forming moiety in a polymer‐supported bifunctional urea–primary amine catalyst, based on (1R, 2R)‐(+)‐1,2‐diphenylethylenediamine, significantly improves the catalyst’s activity and stereoselectivity in the asymmetric addition of ketones and aldehydes to nitroolefins. Yields and enantioselectivities, unprecedented for immobilized catalysts, were obtained with such challenging donors as acetone, cyclopentanone, and α,α‐disubstituted aldehydes, which usually perform inadequately in this reaction (particularly when a secondary‐amine‐based catalyst is used). Remarkably, though in the examined catalysts the D ‐amino acids as spacers were significantly inferior to the L isomers, for the chosen configuration of the diamine (match–mismatch pairs) the size of the side chain of the amino acid hardly influenced the enantioselectivity of the catalyst. These results, combined with the reactivity profile of the catalysts with substrates bearing two electron‐withdrawing groups and the behavior of the catalysts’ analogues based on tertiary (rather than primary) amine, suggest an enamine‐involving addition mechanism and a particular ordered C? C bond‐forming transition state as being responsible for the catalytic reactions with high enantioselectivity. 相似文献
4.
Organocatalytic Enantioselective Aza‐Friedel–Crafts Reaction of Cyclic Ketimines with Pyrroles using Imidazolinephosphoric Acid Catalysts
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Prof. Dr. Shuichi Nakamura Nazumi Matsuda Dr. Mutsuyo Ohara 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(28):9478-9482
Organocatalytic enantioselective aza‐Friedel–Crafts reactions of cyclic ketimines with pyrroles or indoles were catalyzed by imidazoline/phosphoric acid catalysts. The reaction was applied to various 3H‐indol‐3‐ones to afford products in excellent yields and enantioselectivities. The chiral catalysts can be recovered by a single separation step using column chromatography and are reusable without further purification. Based on the experimental investigations, a possible transition state has been proposed to explain the origin of the asymmetric induction. 相似文献
5.
6.
Iridium complex-catalyzed allylic amination of allylic esters 总被引:1,自引:0,他引:1
Takeuchi R Ue N Tanabe K Yamashita K Shiga N 《Journal of the American Chemical Society》2001,123(39):9525-9534
Iridium complex-catalyzed allylic amination of allylic carbonates was studied. The solvent strongly affected the catalytic activity. The use of a polar solvent such as EtOH is essential for obtaining the products in high yield. The reaction of (E)-3-substituted-2-propenyl carbonate and 1-substituted-2-propenyl carbonate with pyrrolidine in the presence of a catalytic amount of [Ir(COD)Cl](2) and P(OPh)(3) (P/Ir = 2) gave a branch amine with up to 99% selectivity. Both secondary and primary amines could be used for this reaction. When a primary amine was used, selective monoallylation occurred. No diallylation product was obtained. The reaction of 1,1-disubstituted-2-propenyl acetate with amines exclusively gave an alpha,alpha-disubstituted allylic amine. This reaction provides an alternative route to the addition of an organometallic reagent to ketimines for the preparation of such amines. The reaction of (Z)-3-substituted-2-propenyl carbonate with amines gave (Z)-linear amines with up to 100% selectivity. In all cases, no (E)-linear amine was obtained. The selectivities described here have not been achieved in similar palladium complex-catalyzed reactions. 相似文献
7.
《应用有机金属化学》2017,31(12)
New polymer supported Cu(II) complexes based on an epoxy functionalized gel type resin were prepared using the multi‐stage procedures. The reactions of epoxy groups with ethylenediamine or tris(2‐aminoethyl)amine, and then NH2 groups with salicylaldehydes were used for the preparation of a series of amine‐imine functionalized polymer supports. Copper(II) acetate was used as a source of metal ions. The complexes were characterized using ICP‐OES, FTIR, DR UV–Vis and TGA techniques, and tested as catalysts in two model C‐N and a series of A3 coupling reactions. Their catalytic activity was rather low in the C‐N coupling reactions between imidazole and iodobenzene or phenylboronic acid. However, the second of the reactions could be conducted effectively under milder conditions. The complexes were efficient used as recyclable catalysts in the A3 coupling reactions. A series of aromatic aldehydes and secondary amines and phenylacetylene could be coupled using 1% mol catalyst. 相似文献
8.
Wang Rendong Li Jian Li Chunju Liu Jun Li Dafeng Jia Xueshun Zhai Hongbin 《中国化学》2010,28(7):1253-1256
The environmentally benign, regio‐ and stereoselective synthesis of functionalized tertiary amine 3 from acetates of Baylis‐Hillman adducts with the aliphatic primary amines in the absence of any solvent and catalysts was reported. 相似文献
9.
New Iridium Catalysts for the Selective Alkylation of Amines by Alcohols under Mild Conditions and for the Synthesis of Quinolines by Acceptor‐less Dehydrogenative Condensation
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Susanne Ruch Dr. Torsten Irrgang Prof. Dr. Rhett Kempe 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(41):13279-13285
A novel family of iridium catalysts stabilised by P,N‐ligands have been introduced. The ligands are based on imidazo[1,5‐b]pyridazin‐7‐amines and can be synthesised with a broad variety of substitution patterns. The catalysts were synthesised quantitatively from the protonated ligands and a commercially available iridium precursor. The catalysts mediate the alkylation of amines by alcohols under mild conditions (70 °C). In addition, the synthesis of quinolines from secondary or primary alcohols and amino alcohols is reported. This sustainable synthesis proceeds through the liberation of two equivalents of water and two equivalents of dihydrogen. The investigations indicate that catalysts suitable for hydrogen autotransfer or borrowing hydrogen chemistry might also be suitable for acceptor‐less dehydrogenative condensation reactions. 相似文献
10.
《Angewandte Chemie (International ed. in English)》2017,56(6):1663-1666
The development of catalytic reactions for synthesizing different compounds from alcohols to save fossil carbon feedstock and reduce CO2 emissions is of high importance. Replacing rare noble metals with abundantly available 3d metals is equally important. We report a manganese‐complex‐catalyzed multicomponent synthesis of pyrimidines from amidines and up to three alcohols. Our reaction proceeds through condensation and dehydrogenation steps, permitting selective C−C and C−N bond formations. β‐Alkylation reactions are used to multiply alkylate secondary alcohols with two different primary alcohols to synthesize fully substituted pyrimidines in a one‐pot process. Our PN5P‐Mn‐pincer complexes efficiently catalyze this multicomponent process. A comparison of our manganese catalysts with related cobalt catalysts indicates that manganese shows a reactivity similar to that of iridium but not cobalt. This analogy could be used to develop further (de)hydrogenation reactions with manganese complexes. 相似文献
11.
A convenient method for the synthesis of 3‐substituted quinazolin‐4(3H)‐ones using the convergent reactions of formic acid, a primary amine, and isatoic anhydride under solvent‐free conditions and with brief microwave irradiation is described. 相似文献
12.
Direct Asymmetric Mannich‐Type Reaction of α‐Isocyanoacetates with Ketimines using Cinchona Alkaloid/Copper(II) Catalysts
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Masashi Hayashi Masaru Iwanaga Noriyuki Shiomi Dr. Daisuke Nakane Prof. Dr. Hideki Masuda Prof. Dr. Shuichi Nakamura 《Angewandte Chemie (International ed. in English)》2014,53(32):8411-8415
The enantioselective direct Mannich‐type reaction of ketimines with α‐isocyanoacetates has been developed. Excellent yields and enantioselectivity were observed for the reaction of various ketimines and α‐isocyanoacetates using cinchona alkaloid/Cu(OTf)2 and a base. Both enantiomers of the products could be obtained by using pseudoenantiomeric chiral catalysts. This process offers an efficient route for the synthesis of α,β‐diamino acids. 相似文献
13.
3D Microporous Base‐Functionalized Covalent Organic Frameworks for Size‐Selective Catalysis
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Dr. Qianrong Fang Dr. Shuang Gu Jie Zheng Dr. Zhongbin Zhuang Prof. Shilun Qiu Prof. Dr. Yushan Yan 《Angewandte Chemie (International ed. in English)》2014,53(11):2878-2882
The design and synthesis of 3D covalent organic frameworks (COFs) have been considered a challenge, and the demonstrated applications of 3D COFs have so far been limited to gas adsorption. Herein we describe the design and synthesis of two new 3D microporous base‐functionalized COFs, termed BF‐COF‐1 and BF‐COF‐2, by the use of a tetrahedral alkyl amine, 1,3,5,7‐tetraaminoadamantane (TAA), combined with 1,3,5‐triformylbenzene (TFB) or triformylphloroglucinol (TFP). As catalysts, both BF‐COFs showed remarkable conversion (96 % for BF‐COF‐1 and 98 % for BF‐COF‐2), high size selectivity, and good recyclability in base‐catalyzed Knoevenagel condensation reactions. This study suggests that porous functionalized 3D COFs could be a promising new class of shape‐selective catalysts. 相似文献
14.
Ryohei Yonesaki Ibuki Kusagawa Hiroyuki Morimoto Tamio Hayashi Takashi Ohshima 《化学:亚洲杂志》2020,15(4):499-502
Enantioselective addition of boronic acids to N‐unsubstituted isatin‐derived ketimines was realized using rhodium(I)/chiral diene catalysts. The reactions can be performed in the presence of catalytic amounts of a base to give adducts in high yield with high enantioselectivity. Preliminary mechanistic information including a computational model to explain the observed enantioselectivity is also provided. 相似文献
15.
Xinjiang Cui Xingchao Dai Prof. Dr. Youquan Deng Dr. Feng Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(11):3665-3675
The N‐alkylation of amines or ammonia with alcohols is a valuable route for the synthesis of N‐alkyl amines. However, as a potentially clean and economic choice for N‐alkyl amine synthesis, non‐noble metal catalysts with high activity and good selectivity are rarely reported. Normally, they are severely limited due to low activity and poor generality. Herein, a simple NiCuFeOx catalyst was designed and prepared for the N‐alkylation of ammonia or amines with alcohol or primary amines. N‐alkyl amines with various structures were successfully synthesized in moderate to excellent yields in the absence of organic ligands and bases. Typically, primary amines could be efficiently transformed into secondary amines and N‐heterocyclic compounds, and secondary amines could be N‐alkylated to synthesize tertiary amines. Note that primary and secondary amines could be produced through a one‐pot reaction of ammonia and alcohols. In addition to excellent catalytic performance, the catalyst itself possesses outstanding superiority, that is, it is air and moisture stable. Moreover, the magnetic property of this catalyst makes it easily separable from the reaction mixture and it could be recovered and reused for several runs without obvious deactivation. 相似文献
16.
Four amine functionalized mesoporous catalysts were synthesized by grafting primary, dualistic and two secondary amines onto the channel walls of mesoporous silica, MCM-41. We examined the effects of organoamine loading amount on the acid-base synergism of the catalysts in the self-condensation reaction of n-butanal, a Knoevenagel condensation and a Henry reaction. We observed the balance of the amine and residual silanol amounts is crucial to the catalytic performances of the functionalized mesoporous catalysts. An optimum organoamine loading amount exists, which is dependent on the organoamine type. There is little difference in the optimum organoamine loading amount between different reactions. The secondary organoamine functionalized MCM-41 exhibits the best catalytic performance in the experimental range. 相似文献
17.
He W Wang L Sun C Wu K He S Chen J Wu P Yu Z 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(47):13308-13317
Versatile syntheses of secondary and tertiary amines by highly efficient direct N‐alkylation of primary and secondary amines with alcohols or by deaminative self‐coupling of primary amines have been successfully realized by means of a heterogeneous bimetallic Pt–Sn/γ‐Al2O3 catalyst (0.5 wt % Pt, Pt/Sn molar ratio=1:3) through a borrowing‐hydrogen strategy. In the presence of oxygen, imines were also efficiently prepared from the tandem reactions of amines with alcohols or between two primary amines. The proposed mechanism reveals that an alcohol or amine substrate is initially dehydrogenated to an aldehyde/ketone or NH‐imine with concomitant formation of a [PtSn] hydride. Condensation of the aldehyde/ketone species or deamination of the NH‐imine intermediate with another molecule of amine forms an N‐substituted imine which is then reduced to a new amine product by the in‐situ generated [PtSn] hydride under a nitrogen atmosphere or remains unchanged as the final product under an oxygen atmosphere. The Pt–Sn/γ‐Al2O3 catalyst can be easily recycled without Pt metal leaching and has exhibited very high catalytic activity toward a wide range of amine and alcohol substrates, which suggests potential for application in the direct production of secondary and tertiary amines and N‐substituted imines. 相似文献
18.
Bifunctional‐Phosphine‐Catalyzed Sequential Annulations of Allenoates and Ketimines: Construction of Functionalized Poly‐heterocycle Rings
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Erqing Li Hongxing Jin Penghao Jia Xuelin Dong Prof. You Huang 《Angewandte Chemie (International ed. in English)》2016,55(38):11591-11594
A highly stereoselective sequential annulation reaction between γ‐substituted allenoates and ketimines was reported. By using bifunctional N‐acyl aminophosphine catalysts, poly‐heterocycle rings were obtained with high stereocontrol in good to excellent yields. The desired products have four contiguous stereogenic centers (one quaternary and three tertiary carbon centers), and only one isomer was obtained in all reactions. 相似文献
19.
Prof. Dr. Fujie Tanaka 《Chemical record (New York, N.Y.)》2023,23(7):e202200207
Carbonyl transformations involving enolates and/or enamines have been used for various types of bond-forming reactions. In this account, catalysts and catalyst systems that have amino acids or primary, secondary, and/or tertiary amines as key catalytic functional groups that we have developed to accelerate chemical transformations, including regio-, diastereo- and enantioselective reactions, are discussed. Our chemical transformation strategies and methods that use amine derivatives as catalysts are also discussed. As amines can have different functions depending on protonation and on the species formed during the catalysis (such as enamines and iminium ions), dynamics and kinetic controls are the keys for understanding the catalysis. Further, strategies that harness dynamic steps and kinetic control in amine-catalyzed reactions have enabled the synthesis of complex molecules in stereocontrolled manners. Understanding the dynamic features and the kinetic controls of the catalysis will further the design of the catalysts and the development of chemical transformation strategies and methods. 相似文献
20.
M. A. Yurovskaya A. Z. Afanas'ev V. A. Chertkov É. M. Gizatullina Yu. G. Bundel' 《Chemistry of Heterocyclic Compounds》1987,23(12):1305-1308
The possibility of using certain ketimines in place of mixtures of ketone and amine in the synthesis of indoles from 3-nitropyridinium salts has been demonstrated. The use of ketimines leads, in many cases, to increased yields of indoles and simplifies their isolation. It has been established that the rate of indole formation is considerably increased in polar aprotic solvents.For Communication 3, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1625–1628, December, 1987. 相似文献