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1. (1,2-Diaminoethane-1,2-diyl)bis(N-methylpyridinium) Salts as a Prospective Platform for Designing Recyclable Prolinamide-Based Organocatalysts

Author:
Lisnyak Vladislav G.; Kucherenko Alexander S.; Valeev Edward F.; Zlotin Sergei G.
Source:
Journal of organic chemistry 2015 v.80 no.19 pp. 9570-9577
ISSN:
1520-6904
Subject:
catalysts; chemical reactions; chemical structure; organic chemistry; organic compounds; salts
Abstract:
... A new efficient and highly recyclable organocatalyst has been developed for asymmetric cross-aldol reactions under neat conditions in ketone–ketone, ketone–aldehyde, and aldehyde–aldehyde systems. The catalyst features two prolinamide fragments and a C₂-symmetrical (1,2-diaminoethane-1,2-diyl)bis(N-methylpyridinium) group. The catalyst retained high activity and excellent stereoselection over the ...
DOI:
10.1021/acs.joc.5b01555

2. (2S,4R)-Hyp-(S)-Phe-OMe dipeptide supported on imidazolium tagged molecules as recoverable organocatalysts for asymmetric aldol reactions using water as reaction medium

Author:
Arturo Obregón-Zúñiga; Eusebio Juaristi
Source:
Tetrahedron 2017 v.73 pp. 5373-5380
ISSN:
0040-4020
Subject:
catalysts; chemical elements; chemical reactions; chemical structure; organic compounds; solvents; stereochemistry
Abstract:
... Four novel chiral imidazolium tagged molecules derived from dipeptide (2S,4R)-Hyp-(S)-Phe-OMe were prepared and evaluated as organocatalysts in the asymmetric aldol reaction using water as solvent. It was found that catalysts incorporating the hexanoyl linker are active down to 5 mol% and afford aldol products with up to 94% yield, up to 98:2 dr and up to 97:3 er. This chiral imidazolium catalyst ...
DOI:
10.1016/j.tet.2017.07.037

3. (Ar-tpy)Ruᴵᴵ(ACN)₃: A Water-Soluble Catalyst for Aldehyde Amidation, Olefin Oxo-Scissoring, and Alkyne Oxygenation

Author:
Dripta De Joarder; Subrata Gayen; Rajarshi Sarkar; Rajarshi Bhattacharya; Sima Roy; Dilip K. Maiti
Source:
Journal of organic chemistry 2019 v.84 no.13 pp. 8468-8480
ISSN:
1520-6904
Subject:
acids; aldehydes; alkynes; amides; carbon-hydrogen bond activation; catalysts; catalytic activity; chemical reactions; chemical structure; ketones; olefin; organic chemistry; ruthenium; water solubility
Abstract:
... The synthetic chemists always look for developing new catalysts, sustainable catalysis, and their applications in various organic transformations. Herein, we report a new class of water-soluble complexes, (Ar-tpy)Ruᴵᴵ(ACN)₃, utilizing designed terpyridines possessing electron-donating and -withdrawing aromatic residues for tuning the catalytic activity of the Ru(II) complex. These complexes displa ...
DOI:
10.1021/acs.joc.9b00487

4. (Dicyclopentadiene) platinum(II) dichloride: an efficient catalyst for the hydrosilylation reaction between alkenes and triethoxysilane

Author:
Huarui Wu; Chaoyue Zheng; Naiwu Chen; Jie Zhu; Deqing Gao
Source:
Tetrahedron letters 2017 pp. -
ISSN:
0040-4039
Subject:
alkenes; biphenyl; catalysts; chemical reactions; isomers; platinum
Abstract:
... (Dicyclopentadiene) platinum(II) dichloride was found to be an efficient hydrosilylation catalyst (homogeneous) upon a wide variety of functionalized alkenes and alkenes terminated with chemical moieties (diphenyl amino-, N-carbazol- and N-isoindoline-1,3-dione-). It is noteworthy that the hydrosilylation of aminated alkenes with triethoxysilane exhibited the yield of over 70% and the selectivity ...
DOI:
10.1016/j.tetlet.2017.03.017

5. (E)-α,β-unsaturated amides from tertiary amines, olefins and CO via Pd/Cu-catalyzed aerobic oxidative N-dealkylation

Author:
Renyi Shi; Hua Zhang; Lijun Lu; Pei Gan; Yuchen Sha; Heng Zhang; Qiang Liu; Matthias Beller; Aiwen Lei
Source:
Chemical communications 2015 v.51 no.15 pp. 3247-3250
ISSN:
1364-548X
Subject:
alkenes; amides; catalysts; catalytic activity; chemical reactions; chemoselectivity; palladium; secondary amines; tertiary amines
Abstract:
... A novel Pd/Cu-catalyzed chemoselective aerobic oxidative N-dealkylation/carbonylation reaction has been developed. Tertiary amines are utilized as a “reservoir” of “active” secondary amines in this transformation, which inhibits the formation of undesired by-products and the deactivation of the catalysts. This protocol allows for an efficient and straightforward construction of synthetically usefu ...
DOI:
10.1039/c4cc08925a

6. (PhC(NtBu)₂Al)₂(SiH₂)₄ six-membered heterocycle: comparable in structure to cyclohexane

Author:
Jiancheng Li; Mingdong Zhong; Helena Keil; Hongping Zhu; Regine Herbst-Irmer; Dietmar Stalke; Sriman De; Debasis Koley; Herbert W. Roesky
Source:
Chemical communications 2019 v.55 no.16 pp. 2360-2363
ISSN:
1364-548X
Subject:
catalysts; chemical bonding; chemical reactions; cyclohexanes
Abstract:
... A silicon–aluminum heterocycle LAl(SiH₂SiH₂)₂AlL (L = PhC(NtBu)₂) (1) was prepared. Compound 1 exhibits a unique (N₂Al)₂(SiH₂)₄ centrosymmetric six-membered ring structure with a chair conformation, which is comparable with that of cyclohexane. Furthermore, two intermediate analogues, silylene–alane adduct LSi(AlMe₃)–Si(AlMe₃)L (2) and silylene–alane oxidative product [LAlHSiH₂Mes]₂ (3) were obtai ...
DOI:
10.1039/c8cc10124h

7. (R)-(+)-N-Methylbenzoguanidine ((R)-NMBG) catalyzed acylative kinetic resolution of racemic 3-hydroxy-3-aryl-propanoates

Author:
Akira Yamada; Kenya Nakata
Source:
Tetrahedron letters 2016 v.57 pp. 4697-4701
ISSN:
0040-4039
Subject:
aromatic compounds; catalysts; chemical reactions; chemical structure; cyclohexanes; esters
Abstract:
... (R)-(+)-N-methylbenzoguanidine ((R)-NMBG) functioned as an efficient acyl transfer catalyst for the acylative kinetic resolution of racemic β-hydroxy esters using cyclohexane carboxylic anhydride under mild reaction conditions. A tert-butyl ester moiety is necessary to achieve a high selectivity. The effects of the substituents on the aromatic rings of the substrates were systematically investigat ...
DOI:
10.1016/j.tetlet.2016.09.014

8. (S)-Threonine/α,α-(S)-diphenylvalinol-derived chiral ionic liquid: an immobilized organocatalyst for asymmetric syn-aldol reactions

Author:
Natalia A. Larionova; Alexandr S. Kucherenko; Dmitry E. Siyutkin; Sergei G. Zlotin
Source:
Tetrahedron 2011 v.67 no.10 pp. 1948-1954
ISSN:
0040-4020
Subject:
aldehydes; carbon; catalysts; chemical reactions; enantiomers; heterocyclic compounds; ionic liquids; ketones
Abstract:
... Chiral ionic liquids containing (S)- or (R)-threonine amide and α,α-(S)-diphenylvalinol units were synthesized In the presence of the (S)-threonine-derived catalyst reactions between ketones with secondary carbon atom(s) at the α-position with respect to the carbonyl group and aromatic (heteroaromatic) aldehydes afforded the corresponding syn-aldols in high yields (up to 99%) and with high diaster ...
DOI:
10.1016/j.tet.2011.01.017

9. (Thio)urea Organocatalyst Equilibrium Acidities in DMSO

Author:
Jakab Gergely; Tancon Carlo; Zhang Zhiguo; Lippert Katharina M.; Schreiner Peter R.
Source:
Organic letters 2012 v.14 no.7 pp. 1724-1727
ISSN:
1523-7052
Subject:
catalysts; chemical reactions; chemical structure; dimethyl sulfoxide; urea
Abstract:
... Bordwell’s method of overlapping indicators was used to determine the pKₐ values of some of the most popular (thio)urea organocatalysts via UV spectrophotometric titrations. The incremental effect of CF₃ groups on acidic strength was also investigated. The pKₐ’s are in the range of 8.5–19.6. The results may lead to a better understanding of noncovalent organocatalysis and may aid in future catalys ...
DOI:
10.1021/ol300307c

10. (Thiolan-2-yl)diphenylmethyl benzyl ether/N,N′-diarylurea cocatalyzed asymmetric aziridination of cinnamyl bromide and aryl aldimine

Author:
Shang-Hua Wang; Rong-Jie Chein
Source:
Tetrahedron 2016 v.72 pp. 2607-2615
ISSN:
0040-4020
Subject:
catalysts; chemical reactions; chemical structure; organic compounds; sulfides
Abstract:
... A dual catalyst system using THT-based chiral sulfide 2a and H-bond donor 10a was developed for the asymmetric imino Corey–Chaykovsky reaction. Under the optimum reaction conditions, cinnamyl bromide reacted with a wide scope of N-diphenylphosphinic aldimines, to give the major trans-aryl cinnamyl aziridines with up to 98% ee. The role of H-bond donor 10a was demonstrated empirically as well. ...
DOI:
10.1016/j.tet.2014.12.063

11. (Z)-Selective cross-dimerization of arylacetylenes with silylacetylenes catalyzed by vinylideneruthenium complexes

Author:
Hiroyuki Katayama; Hiroshi Yari; Masaki Tanaka; Fumiyuki Ozawa
Source:
Chemical communications 2005 v. no.34 pp. 4336-4338
ISSN:
1364-548X
Subject:
catalysts; catalytic activity; chemical reactions; ligands; phosphine
Abstract:
... The vinylideneruthenium(ii) complexes bearing bulky and basic tertiary phosphine ligands, RuCl₂(CCHPh)L₂ (L = PPrⁱ₃, PCy₃), serve as good catalyst precursors for (Z)-selective cross-dimerization between arylacetylenes and silylacetylenes in the presence of N-methylpyrrolidine. ...
DOI:
10.1039/b504436g

12. 1,1-Diamino-2-nitroethylenes as excellent hydrogen bond donor organocatalysts in the Michael addition of carbon-based nucleophiles to β-nitrostyrenes

Author:
Rodrigo C. da Silva; Gustavo P. da Silva; Diego P. Sangi; João G. de M. Pontes; Antônio G. Ferreira; Arlene G. Corrêa; Márcio W. Paixão
Source:
Tetrahedron 2013 v.69 pp. 9007-9012
ISSN:
0040-4020
Subject:
catalysts; chemical reactions; chemical structure; hydrogen bonding; organic compounds
Abstract:
... A new class of hydrogen bond donor catalysts based on the 1,1-diamino-2-nitroethylene scaffold has been introduced for the activation of trans-β-nitrostyrenes toward reactions with a range of carbon-based nucleophiles, affording the corresponding adducts in excellent yields. Importantly, this new set of organocatalysts is easily prepared from commercially available starting materials in mild react ...
DOI:
10.1016/j.tet.2013.08.040

13. 1,2-Diphenylethylenediamine linked chiral Ti(iv) complex—a new entry to the highly enantioselective silylcyanation of aliphatic and aromatic aldehydes

Author:
Chun-Wei Chang; Chun- TzuYang; Chyuan-Der Hwang; Biing-Jiun Uang
Source:
Chemical communications 2002 v. no.1 pp. 54-55
ISSN:
1364-548X
Subject:
aldehydes; catalysts; chemical reactions; enantioselectivity; titanium
Abstract:
... Highly enantioselective silylcyanation of aliphatic and aromatic aldehydes was achieved by using a 1,2-diphenylethylenediamine linked chiral Ti(iv) complex as the catalyst. ...
DOI:
10.1039/b107867d

14. 1,3-Addition of silyl enol ethers to nitrones catalyzed by mesoporous aluminosilicate

Author:
Suguru Ito; Yoshihiro Kubota; Masatoshi Asami
Source:
Tetrahedron letters 2014 v.55 no.35 pp. 4930-4932
ISSN:
0040-4039
Subject:
aldehydes; catalysts; chemical reactions; chemical structure; chemoselectivity; ketones; porous media; silyl enol ethers
Abstract:
... Mesoporous aluminosilicate (Al-MCM-41) was found to be an effective and reusable catalyst for 1,3-addition of silyl enol ethers to nitrones. The reaction proceeded under mild reaction conditions to afford the corresponding β-(siloxyamino)ketones in high yields. Furthermore, a unique chemoselectivity of a nitrone over an aldehyde and an acetal, which are more reactive toward silyl enol ether in the ...
DOI:
10.1016/j.tetlet.2014.07.020

15. 1,3-Bis(2,4,6-trimethylphenyl)imidazolium chloride in combination with triethylamine: an improved catalytic system for hydroacylation/reduction of activated ketones

Author:
M. Sreenivasulu; K. Arun Kumar; K. Sateesh Reddy; K. Siva Kumar; P. Rajender Kumar; K.B. Chandrasekhar; Manojit Pal
Source:
Tetrahedron letters 2011 v.52 no.6 pp. 727-732
ISSN:
0040-4039
Subject:
aldehydes; ambient temperature; catalysts; chemical reactions; chemical structure; ketones; triethylamine
Abstract:
... A rapid, economic, and high yielding methodology has been developed for hydroacylation/reduction of activated ketones by using 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride as a catalyst in combination with triethylamine. The reaction proceeded at an ambient temperature via generating N-heterocyclic carbene in situ that interacted with the (hetero)aryl aldehyde employed. While the reduction o ...
DOI:
10.1016/j.tetlet.2010.12.022

16. 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) an efficient homogeneous catalyst for aldol condensation reactions. Study of the catalyst recovery and reusability using CO₂

Author:
Iuliana Cota; Francisco Medina; Jesús E. Sueiras; Didier Tichit
Source:
Tetrahedron letters 2011 v.52 no.3 pp. 385-387
ISSN:
0040-4039
Subject:
carbon dioxide; chemical reactions; industry; organic compounds; catalysts; odors; chemical structure
Abstract:
... In this work it was shown that TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene), a cheap and commercially available guanidine base, efficiently catalyzes aldol condensation reactions yielding interesting products for pharmacological and fragrance industries. This methodology works under solvent-less conditions and affords with very good conversions the corresponding products. Moreover, a simple and effec ...
DOI:
10.1016/j.tetlet.2010.11.032

17. 1-(1-Alkylsulfonic)-3-methylimidazolium chloride Brönsted acidic ionic liquid catalyzed Skraup synthesis of quinolines under microwave heating

Author:
Ananda S. Amarasekara; Muhammad A. Hasan
Source:
Tetrahedron letters 2014 v.55 no.22 pp. 3319-3321
ISSN:
0040-4039
Subject:
catalysts; chemical reactions; chemical structure; chlorides; ionic liquids; microwave treatment; nitrobenzenes; oxidants; quinolines
Abstract:
... 1-(1-Alkylsulfonic)-3-methylimidazolium chloride Brönsted acidic ionic liquids are shown as excellent catalysts and reaction mediums for Skraup synthesis of quinolines under microwave conditions without the use of nitrobenzene as an oxidant and metal catalysts. ...
DOI:
10.1016/j.tetlet.2014.04.047

18. 1-Methylimidazolium tetrafluoroborate [Hmim][BF4]: an efficient acidic ionic liquid catalyst for insertion of α-diazo compounds into the N–H bonds of amines

Author:
Jafar Akbari; Ali Ebrahimi; Akbar Heydari
Source:
Tetrahedron letters 2014 v.55 no.40 pp. 5417-5419
ISSN:
0040-4039
Subject:
amines; catalysts; chemical bonding; chemical reactions; chemical structure; ionic liquids
Abstract:
... The reusable acidic ionic liquid, 1-methylimidazolium tetrafluoroborate [Hmim][BF4], was found to be an effective catalyst for the insertion of α-diazoacetate into the N–H bonds of amines. The corresponding products were obtained in good yields and short reaction times via a simple procedure. The catalyst could be recycled and reused without any noticeable decrease in its activity. ...
DOI:
10.1016/j.tetlet.2014.08.013

19. 1-Trifluoromethylisoquinolines from α-Benzylated Tosylmethyl Isocyanide Derivatives in a Modular Approach

Author:
Lin Wang; Armido Studer
Source:
Organic letters 2017 v.19 no.20 pp. 5701-5704
ISSN:
1523-7052
Subject:
catalysts; catalytic activity; chemical reactions; chemical structure; organic compounds
Abstract:
... The preparation of various 1-trifluoromethylisoquinolines from α-benzylated tosylmethyl isocyanide derivatives and the commercial Togni reagent using a radical cascade is reported. The starting isocyanides are readily prepared in a modular sequence from commercial tosylmethyl isocyanide via sequential double α-alkylation, and the radical reaction proceeds under mild conditions with high efficiency ...
DOI:
10.1021/acs.orglett.7b02882

20. 11.5% efficiency of TiO₂ protected and Pt catalyzed n⁺np⁺-Si photocathodes for photoelectrochemical water splitting: manipulating the Pt distribution and Pt/Si contact

Author:
Zhihao Yin; Ronglei Fan; Guanping Huang; Mingrong Shen
Source:
Chemical communications 2018 v.54 no.5 pp. 543-546
ISSN:
1364-548X
Subject:
catalysts; cathodes; chemical reactions; coatings; energy conversion; hydrogen; platinum; silicon; titanium dioxide
Abstract:
... A combination of hydrogen passivation, electroless deposition of a Pt catalyst and coating a TiO₂ protective layer leads to an unprecedented 11.5% energy conversion efficiency and one-week stability of an n⁺np⁺-Si photocathode for solar water splitting. ...
DOI:
10.1039/c7cc08409a

21. 2,3-Dimethoxyindolines: a latent electrophile for SNAr reactions triggered by indium catalysts

Author:
Seiya Hirao; Toshiki Yamashiro; Kyouka Kohira; Naoki Mishima; Takumi Abe
Source:
Chemical communications 2020 v.56 no.38 pp. 5139-5142
ISSN:
1364-548X
Subject:
Lewis acids; catalysts; catalytic activity; chemical reactions; indium; indoles
Abstract:
... 2,3-Dimethoxyindolines (DiMeOINs) have emerged as a latent electrophile in indium-catalyzed SNAr reactions. They are easily obtained from commercially available indoles and allowed access to 3-substituted indoles. The reaction proceeds via SNAr reactions of in situ generated 3-methoxyindoles. Formation of C2-substituted indoles was also possible utilizing the C2-nucleophilicity of DIMeOIN. Our pro ...
DOI:
10.1039/d0cc01210f

22. 2,4- vs 3,4-Disubsituted Pyrrole Synthesis Switched by Copper and Nickel Catalysts

Author:
Chen Feng; Shen Tao; Cui Yuxin; Jiao Ning
Source:
Organic letters 2012 v.14 no.18 pp. 4926-4929
ISSN:
1523-7052
Subject:
azides; catalysts; chemical reactions; chemical structure; copper; nickel; pyrroles; regioselectivity
Abstract:
... A novel and efficient copper or nickel catalyzed highly selective denitrogenative annulation of vinyl azides with aryl acetaldehydes has been developed. 2,4- and 3,4-diaryl substituted pyrroles, which are difficult to synthesize by the reported methods, can be highly regioselectively prepared by this protocol simply switched by the selection of the transition metal catalysts. Compared with the rep ...
DOI:
10.1021/ol302270z

23. 2,6-Pyridinedicarboxylic acid as organocatalyst for the synthesis of 1,5-benzodiazepines through one-pot reaction

Author:
Mohan Lal; R. Sidick Basha; Satavisha Sarkar; Abu T. Khan
Source:
Tetrahedron letters 2013 v.54 pp. 4264-4272
ISSN:
0040-4039
Subject:
aldehydes; catalysts; chemical reactions; chemical structure; cost effectiveness
Abstract:
... 2,6-Pyridinedicarboxylic acid has been found to be an effective and efficient organocatalyst for the synthesis of 1,5-benzodiazepine derivatives from o-phenylenediamine, β-ketoesters, and aromatic aldehydes by employing one-pot three-component reaction. The catalyst plays a crucial role for the regioselective C–C bond formation at the γ position of β-ketoesters. The salient features of this presen ...
DOI:
10.1016/j.tetlet.2013.05.148

24. 2,7-Diazabicyclo[2.2.1]heptanes: novel asymmetric access and controlled bridge-opening

Author:
Gary R. Peczkowski; Philip G. E. Craven; Darren Stead; Nigel S. Simpkins
Source:
Chemical communications 2019 v.55 no.29 pp. 4214-4217
ISSN:
1364-548X
Subject:
catalysts; chemical reactions; enantioselectivity; reaction mechanisms
Abstract:
... Organocatalysed asymmetric Michael additions of substituted triketopiperazines to enones afford products in high yield and enantiomeric ratio (er). Further modification delivers products possessing natural product (NP) scaffolds including diazabicyclo[2.2.1]heptane, prolinamide and harmicine. ...
DOI:
10.1039/c8cc10263e

25. 2-(Trifluoromethyl)indoles via Pd(0)-Catalyzed C(sp3)–H Functionalization of Trifluoroacetimidoyl Chlorides

Author:
Pedroni Julia; Cramer Nicolai
Source:
Organic letters 2016 v.18 no.8 pp. 1932-1935
ISSN:
1523-7052
Subject:
catalysts; chemical reactions; chemical structure; chlorides; drugs; indoles; organochlorine compounds
Abstract:
... Perfluoroalkylated indoles are valuable compounds in drug discovery. A Pd(0)-catalyzed C(sp³)–H functionalization enables access to 2-(trifluoromethyl)indoles from trifluoroacetimidoyl chlorides. These are stable compounds, easily obtained from anilines. The cyclization operates with catalyst loadings as low as 1 mol % and accommodates a variety of substituents. ...
DOI:
10.1021/acs.orglett.6b00795

26. 2-Aryl-3,4-dihydropyrans as building blocks for organic synthesis: ring-opening reactions with nucleophiles

Author:
Minghao Li; Yanlong Gu
Source:
Tetrahedron 2011 v.67 no.43 pp. 8314-8320
ISSN:
0040-4020
Subject:
catalysts; chemical reactions; chemical structure; thiols
Abstract:
... An electrophilic ring-opening reaction of 2-aryl-3,4-dihydropyran with many nucleophiles, such as thiophenols, thiols, benzenesulfinic acid, resorcin, 2-methylfuran, benzamide and allyltrimethylsilane, was developed. In the presence of an appropriate catalyst, a product that contains not only a moiety of the nucleophile but also a fragment of 1,3-dicarbonyl compound was obtained. ...
DOI:
10.1016/j.tet.2011.08.075

27. 2-Halogenoimidazolium Salt Catalyzed Aza-Diels–Alder Reaction through Halogen-Bond Formation

Author:
Takeda Youhei; Hisakuni Daichi; Lin Chun-Hsuan; Minakata Satoshi
Source:
Organic letters 2015 v.17 no.2 pp. 318-321
ISSN:
1523-7052
Subject:
aldimines; catalysts; chemical reactions; chemical structure; halogens; salts; titration
Abstract:
... 2-Halogenoimidazolium salts are found to catalyze aza-Diels–Alder reaction of aldimines with Danishefsky diene in an efficient manner. Comparative studies and titration experiments support the formation of halogen bonding between imines and catalysts. ...
DOI:
10.1021/ol503426f

28. 2-Oxo Driven Unconventional reactions: Microwave Assisted Approaches to Tetrahydrofuro[3,2-d]oxazoles and Furanones

Author:
Battini Narsaiah; Battula Satyanarayana; Kumar Raju Ranjith; Ahmed Qazi Naveed
Source:
Organic letters 2015 v.17 no.12 pp. 2992-2995
ISSN:
1523-7052
Subject:
catalysts; chemical reactions; chemical structure; diastereoselective synthesis; metals; microwave treatment; oxazoles
Abstract:
... A highly efficient, novel, microwave-assisted, metal-free, diastereoselective synthesis of tetrahydrofuro[3,2-d]oxazole is disclosed. The synthesis of napthoxazoles is achieved for the first time without the aid of an external catalyst. On the contrary, our reactions generated naphthofuranones when treated in the presence of metals in microwave/thermal conditions. The unusual behavior of our react ...
DOI:
10.1021/acs.orglett.5b01271

29. 2D Ultrafast HMBC 1H,31P: Obtaining Mechanistic Details on the Michaelis–Arbuzov Reaction

Author:
Fernández-Valle María Encarnación; Martínez-Álvarez Roberto; Molero-Vílchez Dolores; Pardo Zulay D.; Sáez-Barajas Elena; Herrera Antonio
Source:
Journal of organic chemistry 2015 v.80 no.2 pp. 799-805
ISSN:
1520-6904
Subject:
bromides; catalysts; chemical reactions; chemical structure; nuclear magnetic resonance spectroscopy; organic chemistry; organic compounds; phosphorus; temperature; zinc
Abstract:
... Ultrafast NMR spectroscopy (UF-NMR) can be used to monitor chemical reactions in real time and to provide insights into their mechanisms and the nature of the intermediates formed. Here, we have developed a 2D ¹H,³¹P UF-HMBC method and the corresponding NMR experimental setup to enable the study of a Michaelis–Arbuzov reaction at two different temperatures, 25 and 70 °C. The specific reaction stud ...
DOI:
10.1021/jo502253p

30. 2H-Azirines as Potential Bifunctional Chemical Linkers of Cysteine Residues in Bioconjugate Technology

Author:
Yang Chen; Wenjie Yang; Jiamin Wu; Wangbin Sun; Teck-Peng Loh; Yaojia Jiang
Source:
Organic letters 2020 v.22 no.5 pp. 2038-2043
ISSN:
1523-7052
Subject:
ambient temperature; catalysts; chemical bonding; chemical reactions; cysteine; moieties; peptides; thiols
Abstract:
... 2H-Azirine-2-caboxamides have been designed to perform as a new type of bifunctional thiol linker under very mild reaction conditions. The cleavage of a C–N double bond of 2H-azirine furnishes an amino amide functional group in situ through a thiol addition and ring-opening process. It works with a broad scope of thiols and 2H-azirines in the absence of any catalysts at room temperature. Cysteine- ...
DOI:
10.1021/acs.orglett.0c00415

31. 3,3′-Disubstituted Oxindoles Formation via Copper-Catalyzed Arylboration and Arylsilylation of Alkenes

Author:
Ren-Xiao Liang; Ru-Yi Chen; Chao Zhong; Jia-Wen Zhu; Zhong-Yan Cao; Yi-Xia Jia
Source:
Organic letters 2020 v.22 no.8 pp. 3215-3218
ISSN:
1523-7052
Subject:
acrylamides; boron; catalysts; catalytic activity; chemical reactions; chemical structure; olefin; organoiodine compounds
Abstract:
... Arylboration and arylsilylation reactions of N-(2-iodoaryl)acrylamides with bis(pinacolato)-diboron (B₂pin₂) or PhMe₂Si-Bpin are developed by using simple CuOAc as the sole catalyst. A range of boron- or silane-bearing 3,3′-disubstituted oxindoles are obtained in moderate to excellent yields. The reaction is proposed to proceed via a domino sequence involving intermolecular olefin borylcupration o ...
DOI:
10.1021/acs.orglett.0c00999

32. 3,4,5-Trimethylphenol and Lewis Acid Dual-Catalyzed Cascade Ring-Opening/Cyclization: Direct Synthesis of Naphthalenes

Author:
Ma He; Hu Xiu-Qin; Luo Yong-Chun; Xu Peng-Fei
Source:
Organic letters 2017 v.19 no.24 pp. 6666-6669
ISSN:
1523-7052
Subject:
Lewis acids; catalysts; chemical bonding; chemical reactions; chemical structure; cleavage (chemistry); naphthalenes
Abstract:
... A 3,4,5-trimethylphenol and Lewis acid dual-catalyzed cascade reaction of donor–acceptor (D–A) cyclopropanes via ring-opening and cyclization is developed. In this reaction, a phenolic compound was used as a covalent catalyst for the first time. Additionally, control experiments proved that 3,4,5-trimethylphenol completed the catalytic cycle by accomplishing the C–C bond cleavage. Using this strat ...
DOI:
10.1021/acs.orglett.7b03392

33. 3,4,9,10-Perylenetetracarboxylic acid/o-phenylenediamine nanomaterials as novel redox probes for electrochemical aptasensor systems based on an Fe₃O₄ magnetic bead as a nonenzymatic catalyst

Author:
Yuanyuan Chang; Shunbi Xie; Yaqin Chai; Yali Yuan; Ruo Yuan
Source:
Chemical communications 2015 v.51 no.36 pp. 7657-7660
ISSN:
1364-548X
Subject:
aptasensors; carboxylic acids; catalysts; chemical reactions; electrochemistry; iron oxides; magnetism; nanomaterials; thrombin
Abstract:
... A novel redox probe 3,4,9,10-perylenetetracarboxylic acid/o-phenylenediamine (PTCA/OPD) with well-defined redox peaks caused by the synergistic action between them was demonstrated via theoretical and practical research, and applied in an electrochemical aptasensor to detect thrombin (TB) based on an Fe₃O₄ magnetic bead (MB) as a nonenzymatic catalyst. ...
DOI:
10.1039/c5cc00684h

34. 3-Alkenylation or 3-Alkylation of Indole with Propargylic Alcohols: Construction of 3,4-Dihydrocyclopenta[b]indole and 1,4-Dihydrocyclopenta[b]indole in the Presence of Different Catalysts

Author:
Zhang Li; Zhu Yuanxun; Yin Guangwei; Lu Ping; Wang Yanguang
Source:
Journal of organic chemistry 2012 v.77 no.21 pp. 9510-9520
ISSN:
1520-6904
Subject:
alcohols; boron; catalysts; chemical reactions; chemical structure; copper; indoles; organic chemistry
Abstract:
... 3-Alkenylation or 3-alkylation of indole with propargylic alcohols could be efficiently controlled by the catalyst. In the presence of triflic acid, 3-alkenylation of indole occurred and a 3,4-dihydrocyclopenta[b]indole skeleton was effectively constructed in moderate to excellent yields via a cascade process. In the presence of Cu(OTf)₂, 3-alkylation of indole resulted in the formation of 3-propa ...
DOI:
10.1021/jo300339a

35. 3-Quinuclidinol as a nucleophilic catalyst for the cyanation of 2-chloropyrimidines

Author:
Hong-Yong Kim; Wen-Chung Shieh; Mahavir Prashad
Source:
Tetrahedron letters 2014 v.55 no.36 pp. 5055-5057
ISSN:
0040-4039
Subject:
Lewis bases; catalysts; chemical reactions; chemical structure; organic compounds; potassium cyanide
Abstract:
... 3-Quinuclidinol serves as an effective nucleophilic catalyst for the preparation of 2-cyanopyrimidines by cyanation of 2-chloropyrimidines with potassium cyanide in good yields. ...
DOI:
10.1016/j.tetlet.2014.07.033

36. 31P NMR Chemical Shifts of Phosphorus Probes as Reliable and Practical Acidity Scales for Solid and Liquid Catalysts

Author:
Zheng Anmin; Liu Shang-Bin; Deng Feng
Source:
Chemical Reviews 2017 v.117 no.19 pp. 12475-12531
ISSN:
1520-6890
Subject:
Fourier transform infrared spectroscopy; acidity; ammonia; calorimetry; catalysts; catalytic activity; chemical reactions; desorption; liquids; nuclear magnetic resonance spectroscopy; oxides; pH; petrochemicals; phosphorus; porous media; reaction mechanisms; rendering; stable isotopes; titration; zeolites
Abstract:
... Acid–base catalytic reaction, either in heterogeneous or homogeneous systems, is one of the most important chemical reactions that has provoked a wide variety of industrial catalytic processes for production of chemicals and petrochemicals over the past few decades. In view of the fact that the catalytic performances (e.g., activity, selectivity, and reaction mechanism) of acid-catalyzed reactions ...
DOI:
10.1021/acs.chemrev.7b00289

37. 3D Nanoporous FeAl-KIT-5 with a cage type pore structure: a highly efficient and stable catalyst for hydroarylation of styrene and arylacetylenes

Author:
Shaji Varghese; Samuthira Nagarajan; Mercy R. Benzigar; Ajayan Mano; Zeid A. ALOthman; George Allen Gnana Raj; Ajayan Vinu
Source:
Tetrahedron letters 2012 v.53 no.12 pp. 1485-1489
ISSN:
0040-4039
Subject:
alkanes; alkenes; catalysts; chemical reactions; chemical structure; styrene; surface area
Abstract:
... A novel bimetallic nanoporous FeAl-KIT-5 catalyst with a cage type porous structure and a high surface area has been prepared for the hydroarylation of styrene and arylacetylenes to afford 1,1-diarylalkanes and 1,1-diarylalkenes, respectively. The catalyst was found to be highly active, and selective, affording a high yield of substituted alkanes and alkenes. The catalyst also showed much higher a ...
DOI:
10.1016/j.tetlet.2012.01.040

38. 3D spongy nanofiber structure Fe–NC catalysts built by a graphene regulated electrospinning method

Author:
Weiyuan Ding; Hongquan Yu; Yu Tang; Zhuxin Li; Bijiao Liu; Dechong Liu; Yuyu Wang; Shu hong Liu; Hong Zhao; Daniel Mandler
Source:
Chemical communications 2020 v.56 no.46 pp. 6277-6280
ISSN:
1364-548X
Subject:
carbon nanotubes; catalysts; catalytic activity; chemical reactions; electrochemistry; graphene; macropores; nanofibers; platinum
Abstract:
... 3D spongy nanofiber structure Fe–NC catalysts were constructed by a graphene regulated electrospinning method. The framework of the catalysts was reconstructed into carbon nanotubes, mesopores and macropores, and most of the Fe₃C is converted to Fe₂N during the calcination process. All catalysts showed better electrocatalytic performances than commercial Pt/C. ...
DOI:
10.1039/d0cc01517b

39. 4-(Dimethylamino)pyridine as a catalyst for the lactonization of 4-hydroxy-2-methylenebutanoate esters

Author:
Daniel R. Nicponski
Source:
Tetrahedron letters 2014 v.55 pp. 2075-2077
ISSN:
0040-4039
Subject:
catalysts; chemical reactions; chemical structure; esters; pyridines
Abstract:
... The catalytic action of 4-(dimethylamino)pyridine (DMAP) in lactonizing 4-hydroxy-2-methylenebutanoate esters to 2-methylene-γ-butyrolactones is described. The use of DMAP, which functions as an excellent complement to the more traditional acid-catalyzed lactonization protocol, allows for the synthesis of 2-methylene-γ-butyrolactones containing acid-sensitive groups under essentially neutral condi ...
DOI:
10.1016/j.tetlet.2014.02.024

40. 4-Dimethylaminopyridine-catalyzed multi-component one-pot reactions for the convenient synthesis of spiro[indoline-3,4′-pyrano[2,3-c]pyrazole] derivatives

Author:
Jun Feng; Keyume Ablajan; Ahat Sali
Source:
Tetrahedron 2014 v.70 pp. 484-489
ISSN:
0040-4020
Subject:
catalysts; chemical reactions; chemical structure; ethanol; hydrazine
Abstract:
... An efficient and clean reaction process was developed for the convenient and cheap synthesis of spirooxindole derivatives. One-pot reactions of isatins, malononitrile (or ethyl cyanoacetate), hydrazine hydrate (or phenylhydrazine), and 1,3-dicarbonyl compounds were compared with one-pot reactions of isatins, malononitrile (or ethyl cyanoacetate), and 5-pyrazolone derivatives. Both sets of reaction ...
DOI:
10.1016/j.tet.2013.11.019

41. 5-Aryl-2-(2-hydroxyphenyl)furan-3-carbaldehyde: synthesis and study on its ring-chain tautomerism

Author:
Jaydip Ghosh; Pritam Biswas; Tapas Sarkar; Michael G.B. Drew; Chandrakanta Bandyopadhyay
Source:
Tetrahedron letters 2016 v.57 pp. 3354-3357
ISSN:
0040-4039
Subject:
catalysts; chemical reactions; chemical structure; organic compounds; silver nitrate; solvents
Abstract:
... An efficient transformation of 3-(1-alkynyl)chromone 1 to 2-(2-hydroxyphenyl)-5-phenylfuran-3-carbaldehyde 2 has been accomplished using AgNO3 as catalyst. The ring-chain tautomerism of 2 depends on solvent and substituent. ...
DOI:
10.1016/j.tetlet.2016.06.069

42. 5.1% efficiency of Si photoanodes for photoelectrochemical water splitting catalyzed by porous NiFe (oxy)hydroxide converted from NiFe oxysulfide

Author:
Wanyi Zhou; Ronglei Fan; Taozheng Hu; Guanping Huang; Weng Dong; Xi Wu; Mingrong Shen
Source:
Chemical communications 2019 v.55 no.84 pp. 12627-12630
ISSN:
1364-548X
Subject:
catalysts; catalytic activity; chemical reactions; electrochemistry; nickel; photochemistry; silicon; sodium hydroxide
Abstract:
... A porous NiFe (oxy)hydroxide catalyst fabricated on n⁺pp⁺-Si/Ni/NiOₓ, which is converted from an electrodeposited NiFe oxysulfide, allows a silicon photoanode for water splitting to hit a record 5.1% efficiency with good stability of up to 135 h under 40 mA cm⁻² in 1.0 M NaOH. ...
DOI:
10.1039/c9cc06413c

43. 6,6′-Thiobis(methylene)-β-cyclodextrin dimer as a dimeric host and reusable promoter for synthesis of chromenones in water

Author:
Vijay Vilas Shinde; Daham Jeong; Eunae Cho; Seunho Jung
Source:
Tetrahedron 2018 v.74 pp. 194-198
ISSN:
0040-4020
Subject:
beta-cyclodextrin; catalysts; chemical reactions; chemical structure; nuclear magnetic resonance spectroscopy; organic compounds; reaction mechanisms; recycling; solvents; spectral analysis
Abstract:
... Herein, two unit of β-cyclodextrin linked by thiomethylene bridge was synthesized and employed as a novel efficient supramolecular host for the synthesis of biologically active chromenones templates via three-component single-pot reaction. A possible reaction mechanism through molecular complexation is suggested based on 2D ROESY NMR spectroscopic analysis. Moreover, the catalyst could be easily r ...
DOI:
10.1016/j.tet.2017.11.065

44. 9-Borabicyclo[3.3.1]nonane: a metal-free catalyst for the hydroboration of carbodiimides

Author:
Alberto Ramos; Antonio Antiñolo; Fernando Carrillo-Hermosilla; Rafael Fernández-Galán; Daniel García-Vivó
Source:
Chemical communications 2019 v.55 no.21 pp. 3073-3076
ISSN:
1364-548X
Subject:
catalysts; chemical bonding; chemical reactions; heterocyclic compounds; stoichiometry
Abstract:
... The commercial 9-borabicyclo[3.3.1]nonane dimer is used as the first example of a metal-free catalyst for the monohydroboration of carbodiimides with pinacol borane. Stoichiometric reactions, kinetic studies, and DFT calculations have allowed us to propose a plausible mechanism involving a heterocyclic amidinate intermediate with a three center-two electron B–H–B bond. ...
DOI:
10.1039/c9cc00593e

45. 9-Thiourea Cinchona alkaloid supported on mesoporous silica as a highly enantioselective, recyclable heterogeneous asymmetric catalyst

Author:
Peng Yu; Jing He; Canxiong Guo
Source:
Chemical communications 2008 v. no.20 pp. 2355-2357
ISSN:
1364-548X
Subject:
Cinchona; alkaloids; catalysts; chemical reactions; enantioselectivity; imines; indoles; porous media; silica
Abstract:
... A readily recycled and regenerated heterogeneous catalyst of 9-thiourea epi-quinine supported on mesoporous silica exhibits enhanced enantioselectivity (up to 99.2%) in the asymmetric Friedel–Crafts reaction of imines with indoles. ...
DOI:
10.1039/b800640g

46. A 1,5-benzothiazepine synthesis

Author:
Christopher B.W. Phippen; Christopher S.P. McErlean
Source:
Tetrahedron letters 2011 v.52 no.13 pp. 1490-1492
ISSN:
0040-4039
Subject:
catalysts; chemical reactions; chemical structure; organic compounds; solvents
Abstract:
... The pharmaceutically active compound (±)-thiazesim was synthesized in four steps and 62% overall yield. This new approach to biologically relevant benzothiazepine ring systems features the use of water as a solvent, co-solvent or catalyst in three of the four steps. ...
DOI:
10.1016/j.tetlet.2011.01.098

47. A 3-D diamondoid MOF catalyst based on in situ generated [Cu(L)₂] N-heterocyclic carbene (NHC) linkers: hydroboration of CO₂

Author:
Alexandre Burgun; Rachel S. Crees; Marcus L. Cole; Christian J. Doonan; Christopher J. Sumby
Source:
Chemical communications 2014 v.50 no.79 pp. 11760-11763
ISSN:
1364-548X
Subject:
carbenes; carbon dioxide; catalysts; chemical reactions; copper; heterocyclic nitrogen compounds; moieties
Abstract:
... A new MOF, [Zn₄O{Cu(L)₂}₂] (1), with a 4-fold interpenetrated 3D diamondoid structure was synthesised from in situ generated [Cu(L)₂] NHC linkers. MOF 1 possesses tetrahedral Zn₄O nodes, which are unusually coordinated by four pairs of carboxylates from four [Cu(L)₂] linkers, and 14 Å 1-D pore channels lined with [Cu(L)₂] moieties that catalyse the hydroboration of CO₂. ...
DOI:
10.1039/c4cc04761c

48. A 3d-printed composite electrode for sustained electrocatalytic oxygen evolution

Author:
Si Liu; Rongji Liu; Dandan Gao; Ivan Trentin; Carsten Streb
Source:
Chemical communications 2020 v.56 no.60 pp. 8476-8479
ISSN:
1364-548X
Subject:
catalysts; catalytic activity; chemical reactions; electrochemistry; electrodes; iron; nickel; oxygen production; three-dimensional printing
Abstract:
... We report the facile design and fabrication of 3D-printed microstructured electrodes for electrocatalytic oxygen evolution. ABS polymer-based mesh scaffolds are chemically functionalized to enable electroless nickel metal deposition and subsequent catalyst (nickel iron hydroxide) immobilization. The resulting composites show sustained oxygen evolution with low overpotentials and high stability. Th ...
DOI:
10.1039/d0cc03579c

49. A BEt₃-Base Catalyst for Amide Reduction with Silane

Author:
Wubing Yao; Huaquan Fang; Qiaoxing He; Dongjie Peng; Guixia Liu; Zheng Huang
Source:
Journal of organic chemistry 2019 v.84 no.10 pp. 6084-6093
ISSN:
1520-6904
Subject:
aldimines; amides; amines; catalysts; chemical reactions; chemical structure; hydrides; nitriles; organic chemistry; silane; silicon
Abstract:
... Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines und ...
DOI:
10.1021/acs.joc.9b00277

50. A Bicyclic N-Heterocyclic Carbene as a Bulky but Accessible Ligand: Application to the Copper-Catalyzed Borylations of Aryl Halides

Author:
Ando Shin; Matsunaga Hirofumi; Ishizuka Tadao
Source:
Journal of organic chemistry 2015 v.80 no.19 pp. 9671-9681
ISSN:
1520-6904
Subject:
ambient temperature; carbenes; catalysts; chemical reactions; chemical structure; copper; heterocyclic nitrogen compounds; ligands; nitrogen; organic chemistry; organic halogen compounds
Abstract:
... Imidazol-2-ylidene and imidazolin-2-ylidene are frequently employed as the core structures of N-heterocyclic carbene (NHC) ligands, because these have two nitrogen sites adjacent to carbenic carbons. The electronic and steric effects of N-substituents to a bound metal have been aptly studied, and bulky substituents have commonly been introduced on nitrogen(s). However, too much bulkiness can somet ...
DOI:
10.1021/acs.joc.5b01721