- Deaminative Olefination of Methyl N-Heteroarenes by an Amine Oxidase Inspired Catalyst
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We explored the bioinspired o-quinone cofactor catalyzed aerobic primary amine dehydrogenation for a cascade olefination reaction with nine different methyl N-heteroarenes, including pyrimidines, pyrazines, pyridines, quinolines, quinoxolines, benzimidazoles, benzoxazoles, benzthiazoles, and triazines. An o-quinone catalyst phd (1,10-phenanthroline-5,6-dione) combined with a Br?nsted acid catalyzed the reaction. N-Heteroaryl stilbenoids were synthesized in high yields and (E)-selectivities under mild conditions using oxygen (1 atm) as the sole oxidant without needing transition-metal salt, ligand, stoichiometric base, or oxidant.
- Thorve, Pradip Ramdas,Maji, Biplab
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supporting information
p. 542 - 547
(2021/01/26)
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- Metal-Free Synthesis of Alkenylazaarenes and 2-Aminoquinolines through Base-Mediated Aerobic Oxidative Dehydrogenation of Benzyl Alcohols
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A metal-free, base-mediated, and atom-efficient oxidative dehydrogenative coupling of substituted phenylmethanols (benzyl alcohols) with methyl azaarenes or phenylacetonitriles to afford substituted alkenylazaarenes or 2-aminoquinolines, respectively is described. CsOH.H2O was discovered to be the base of choice for obtaining optimal yields of the title compounds, although the reaction could proceed with KOH as well. The protocol that works efficiently in the presence of air is amenable over broad range of substrates.
- Batra, Sanjay,Dahatonde, Dipak J.,Ghosh, Aritra
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p. 2746 - 2751
(2021/06/25)
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- Catalytic activity of Pd dithiolate complexes with large-bite-angle diphosphines in Heck coupling reactions
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Palladium(II) complexes of aryl dithiolates and wide-bite-angle diphosphines Xantphos and dppf have been developed as efficient catalysts in Suzuki and Suzuki carbonylation reactions. The catalytic activity of these highly stable, discrete and charged complexes was investigated in Heck coupling reactions of styrene and a variety of aryl bromides. Under optimized reaction conditions these palladium complexes showed excellent activity with high turnover number (6 × 106) and high turnover frequency (4 × 105 h?1). The effect of bite angle of diphosphines on the catalytic activity of the complexes [Pd2(P∩P)2(SC12H8S)]2(OTf)4 followed the trend P∩P = Xantphos > dppf > dppe as the order of their bite angles. The catalyst could be reused, and after three cycles the formation of significant amount of Pd nanoparticles was noticed, which were characterized using powder X-ray diffraction, energy-dispersive X-ray analysis and transmission electron microscopy. The high catalytic activity has been attributed to the Pd nanoparticles.
- Mane, Pravin A.,Neogy, Suman,Dey, Sandip
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- Iron/TEMPO-catalyzed direct aerobic oxidative coupling of methyl-mubstituted N-heteroazaarenes with alcohols
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A novel direct oxidative coupling of methyl-substituted N-heteroazaarenes with alcohols has been developed to construct olefins under mild condition. The reaction is catalyzed by Fe(NO3)3·9H2O/TEMPO with oxygen as terminal oxidant. A variety of E-disubstituted olefins bearing diverse functional groups could be obtained selectively in moderate to excellent yields. The reaction is environmentally friendly and ligand-free.
- Zhang, Zhiguang,Ma, Yantao,Dai, Siwei,Li, Ling,Zhang, Yong,Li, Hao
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supporting information
(2020/04/21)
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- MnO2 mediated sequential oxidation/olefination of alkyl-substituted heteroarenes with alcohols
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A practical and efficient ligand-free MnO2 mediated sequential oxidation and olefination has been developed for the facile synthesis of a broad range of unsaturated N-heteroazaarenes from simple alkyl-substituted heteroarenes and alcohols. The procedure tolerates a series of functional groups, such as methoxyl, chloro, bromo, iodo, vinyl, phenolic and hetero groups, providing the olefination products in moderate to good yields.The protocol could be conducted at mild conditions and used environmentally friendly air as the clear oxidant.
- Zhang, Chunyan,Li, Zehua,Fang, Yanchen,Jiang, Shaohua,Wang, Maorong,Zhang, Guoying
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supporting information
(2020/02/15)
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- Preparation method of trans-disubstituted olefin
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The invention relates to the technical field of organic chemical synthesis, and in particular, relates to a preparation method of trans-disubstituted olefin. According to the preparation method, primary alcohol and methyl azacycle are taken as raw materials, transition metal salt, nitric oxide and alkali are taken as catalysts, an organic solution is taken as a reaction medium, and reaction is carried out in an oxygen atmosphere. According to the preparation method, a reaction by-product is only water, the environment is not polluted, the required transition metal catalyst is cheap and easy toobtain, the reaction does not need high temperature, and the reaction cost and the requirements on reaction conditions can be reduced.
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Paragraph 0126-0133
(2020/02/27)
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- Nickel-Catalyzed Direct Alkenylation of Methyl Heteroarenes with Primary Alcohols
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An efficient nickel-catalyzed acceptorless dehydrogenative coupling of methyl-substituted heteroarenes with primary alcohols is achieved using an in situ generated complex of inexpensive NiBr2 and readily available 8-aminoquinoline picolinic amide ligand. The protocol is operationally simple and scalable and furnishes a series of high-value 2-alkenylheteroarenes in good yields (up to 88percent) with exclusive E-selectivity. The reaction proceeds with the release of water and molecular hydrogen, which was analyzed through gas chromatography to validate the reaction mechanism. ?
- Baidya, Mahiuddin,Ramakrishna, Isai,Ramalingam, Bose Muthu
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p. 9819 - 9825
(2019/08/26)
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- Nickel-catalysed direct α-olefination of alkyl substituted N-heteroarenes with alcohols
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Catalytic α-olefination of alkylheteroarenes with primary alcohols via dehydrogenative coupling is presented. A simple nickel catalyst system stabilised by readily available nitrogen ligands enables a series of interesting E-configured vinylarenes (confirmed by X-ray crystal-structure analysis) to be synthesised in good to excellent yields with olefin/alkane selectivity of >20:1. Hydrogen and water are generated as byproducts and quantitative determination of H2 was performed.
- Das, Jagadish,Vellakkaran, Mari,Banerjee, Debasis
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supporting information
p. 7530 - 7533
(2019/07/04)
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- Iron-Catalyzed Coupling of Methyl N-Heteroarenes with Primary Alcohols: Direct Access to E-Selective Olefins
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An efficient Fe-catalyzed system is reported for direct α-olefination of methyl-substituted N-heteroarenes with primary alcohols. The catalytic dehydrogenative coupling enables a series of functionalized E-olefinated N-heteroaromatics with excellent selectivity (>99%). Initial mechanistic studies including deuterium-labeling experiments provide evidence for the participation of the benzylic C-H/D bond of alcohols.
- Das, Jagadish,Vellakkaran, Mari,Sk, Motahar,Banerjee, Debasis
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supporting information
p. 7514 - 7518
(2019/10/02)
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- Manganese-Catalyzed Direct Olefination of Methyl-Substituted Heteroarenes with Primary Alcohols
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Herein, we present the first catalytic direct olefination of methyl-substituted heteroarenes with primary alcohols through an acceptorless dehydrogenative coupling. The reaction is catalyzed by a complex of the earth-abundant transition metal manganese that is stabilized by a bench-stable NNN pincer ligand derived from 2-hydrazinylpyridine. The reaction is environmentally benign, producing only hydrogen and water as byproducts. A large number of E-disubstituted olefins were selectively obtained with high efficiency.
- Barman, Milan K.,Waiba, Satyadeep,Maji, Biplab
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supporting information
p. 9126 - 9130
(2018/07/25)
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- Macrocyclic Pd(II) dithiolate complexes as catalysts in Heck reactions
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The supramolecular palladium dithiolate complexes, [Pd2(dppe)2{S(C6H4)nS}]2(OTf)4and [Pd2(dppe)2(SCH2C6H4CH2S)]
- Mane, Pravin A.,Dey, Sandip,Vivekananda
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- Direct alkenylation of alkylazaarenes with aldehydes through C(sp3)-H functionalization under catalytic InCl3 activation
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Under the influence of InCl3 as a Lewis acid catalyst, a methodology on the C(sp3)-H functionalization of alkylazaarenes has been demonstrated through the activation of benzylic C-H bonds towards their addition reaction with the appropriate electrophiles. This methodology was chiefly applied in the direct alkenylation of primary and secondary benzylic C-H bonds of alkylazaarenes with aldehydes. A variety of alkenyl products were afforded in generally good yields including the starting alkenyl intermediate used in the synthesis of montelukast and other related molecules.
- Jamal, Zaini,Teo, Yong-Chua,Lim, Gina Shiyun
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p. 2132 - 2138
(2016/04/19)
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- Oxidative olefination of secondary amines with carbon nucleophiles
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An unprecedented olefination reaction of secondary amines with carbon nucleophiles has been developed through C-N/C-H functionalization under metal-free oxidative conditions. In the presence of a stoichiometric amount of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), a range of secondary N-alkylanilines smoothly underwent oxidative olefination with 2-alkylazaarenes, acetophenone, and malononitrile to give structurally diverse polysubstituted alkenes in moderate to excellent yields with excellent (E) selectivity. Preliminary mechanistic studies revealed that the oxidative olefination reaction proceeds through amine oxidation followed by imine olefination. A range of secondary N-alkylanilines smoothly underwent DDQ-promoted oxidative olefination with 2-alkylazaarenes, acetophenone, and malononitrile to give structurally diverse alkenes in moderate to excellent yields with excellent (E) selectivity. Mechanistically, the reaction proceeds through amine oxidation followed by imine olefination (DDQ = 2,3-dichloro-5,6-dicyano-1,4-benzoquinone). Copyright
- Zhang, Yong-Gang,Xu, Jing-Kun,Li, Xi-Ming,Tian, Shi-Kai
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supporting information
p. 3648 - 3652
(2013/07/19)
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- Effect of the nitrogen heteroatom on the photophysics and photochemistry of trans-1-styrylnaphthalene and trans-9-styrylphenanthrene in different solvents
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The effect of the nitrogen heteroatom on the excited state properties of trans-1-styrylnaphthalene (1-StN) and trans-9-styrylphenanthrene (9-StPh) has been investigated by fluorimetric and photochemical techniques.The relaxation processes of two aza analo
- Bartocci, Giampiero,Mazzucato, Ugo,Spalletti, Anna
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p. 459 - 464
(2007/10/03)
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