- Black phosphorus as a metal-free, visible-light-active heterogeneous photoredox catalyst for the direct C-H arylation of heteroarenes
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Black phosphorus (BP) is for the first time employed as a metal-free, heterogeneous photoredox catalyst for the direct C-H arylation of heteroarenes with aryl diazonium salts. The arylated heteroarenes are obtained in moderate to good yields under visible-light illumination, and the protocol is shown to be applicable for the scale-up synthesis.
- Kalay, Erbay,Kü?ükke?eci, Hüseyin,Kilic, Haydar,Metin, ?nder
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supporting information
p. 5901 - 5904
(2020/06/04)
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- Carbazole based Electron Donor Acceptor (EDA) catalysis for the synthesis of biaryl and aryl-heteroaryl compounds
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A highly regioselective, carbazole based Electron Donor Acceptor (EDA) catalyzed synthesis of biaryl and aryl-heteroaryl compounds is described. Various indole and carbazole derivatives were screened for the Homolytic Aromatic Substitution (HAS) reaction. Tetrahydrocarbazole (THC) was very efficient for the HAS transformation and proceeded via a complex formation between diazonium salt and electron rich tetrahydrocarbazole. The UV-Vis spectroscopy technique has been used to confirm the complex formation. The in situ generated EDA complex even in a catalytic amount is found to be efficient for the Single Electron Transfer (SET) process without any photoactivation. Biaryl compounds, 2-phenylfuran, 2-phenylthiophene, and 2-phenylpyrrole and bioactive compounds such as dantrolene and canagliflozin have been synthesized in moderate to excellent yields.
- Annes, Sesuraj Babiola,Ramesh, Subburethinam,Saravanan, Subramanian,Saritha, Rajendhiran
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supporting information
p. 2510 - 2515
(2020/04/15)
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- Cycloisomerization of Conjugated Allenones into Furans under Mild Conditions Catalyzed by Ligandless Au Nanoparticles
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Au nanoparticles supported on TiO2 (1 mol %) catalyze the quantitative cycloisomerization of conjugated allenones into furans under very mild conditions. The reaction rate is accelerated by adding acetic acid (1 equiv), but the acid does not participate in the protodeauration step as in the corresponding Au(III)-catalyzed transformation. The process is purely heterogeneous, allowing thus the recycling and reuse of the catalyst effectively in several runs.
- Zorba, Leandros,Kidonakis, Marios,Saridakis, Iakovos,Stratakis, Manolis
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p. 5552 - 5555
(2019/08/01)
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- Transition-Metal-Free Heterobiaryl Synthesis via Aryne Coupling
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We disclose, for the first time, an efficient route for the construction of various heterobiaryl backbones in fair to excellent yields using the Aryne coupling methodology. This study outlined the remarkable effect of external chelating ligands and salt additives on the heterocyclic partner reactivity in the aryne coupling reaction.
- Saied, Tarak,Demangeat, Catherine,Panossian, Armen,Leroux, Frédéric R.,Fort, Yves,Comoy, Corinne
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supporting information
p. 5275 - 5284
(2019/03/27)
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- Ditriaromatic amine compound containing five-membered ring spiral structure, application thereof and light-emitting device
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The invention provides a ditriaromatic amine compound containing a five-membered ring spiral structure, which has a following structural formula shown as the specification. The compound has good thermal stability, high luminous efficiency and high lumines
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Paragraph 0050; 0052; 0053; 0054; 0060; 0061; 0062
(2019/04/10)
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- Continuous Visible-Light Photoflow Approach for a Manganese-Catalyzed (Het)Arene C?H Arylation
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Manganese photocatalysts enabled versatile room-temperature C?H arylation reactions by means of continuous visible-light photoflow, thus allowing for efficient C?H arylations in 30 minutes with ample scope. The robustness of the manganese-catalyzed photoflow strategy was shown by visible light-induced gram-scale synthesis, clearly outperforming the batch performance.
- Liang, Yu-Feng,Steinbock, Ralf,Yang, Long,Ackermann, Lutz
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supporting information
p. 10625 - 10629
(2018/08/01)
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- Visible-Light-Promoted Arylation Reactions Photocatalyzed by Bismuth(III) Oxide
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Bismuth(III) oxide has been successfully applied as a photocatalyst in the arylation of heteroarenes with diazonium salts. With a low catalyst loading (1 to 5 mol-%), this cheap and nontoxic semiconductor could efficiently promote the formation of the aryl radical under visible light irradiation. The arylated products are obtained in moderate to good yields, and the process admits straightforward scale-up (10 mmol; 1 mol-% Bi2O3). In two cases, the diazonium salt was generated in situ and used in the photocatalytic arylation in a tandem manner. Besides heteroarenes, Bi2O3 also catalyzed the arylation of differently substituted alkenes and alkynes, thus representing a viable and practical alternative to the more commonly used ruthenium complexes and organic dyes.
- Buglioni, Laura,Riente, Paola,Palomares, Emilio,Pericàs, Miquel A.
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supporting information
p. 6986 - 6990
(2017/12/26)
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- Polyaniline-Induced Arylation with Arenediazonium Salts Derived from Anilines
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A catalytic amount of a reduced form of polyaniline (a redox-active π-conjugated polymer) was found to induce C?H direct arylation of (hetero)arenes with arenediazonium salts prepared from anilines with methanesulfonic acid (MeSO3H) and tert-butyl nitrite (tBuONO). The difficult part of this method is the coexistence of an oxidant and a reductant in this sequential diazotization and arylation system; diazotization requires weak oxidants such as alkyl nitrites, whereas the arylation is induced by a reductant. This was achieved by the careful control of the amount of tBuONO (1.0 equivalent) for the diazotization step, and sequential arylation using 5 mol % of the polyaniline. The reaction took place under mild conditions without any metals or strong bases at room temperature, and the amino group is a formal leaving group. The scope of the substrates demonstrates the versatility in the combination of anilines with a variety of functional groups and several (hetero)arenes. Two-directional arylation for the synthesis of an unsymmetrical 1,4-diarylated (furyl and pyrrolyl groups) benzene was achieved, using mono-Boc-protected 1,4-phenylenediamine as a substrate. This shows potential for the synthesis of more complicated oligoarene compounds.
- Hata, Dai,Moriuchi, Toshiyuki,Hirao, Toshikazu,Amaya, Toru
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supporting information
p. 7703 - 7709
(2017/06/06)
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- Porphyrin-Catalyzed Photochemical C–H Arylation of Heteroarenes
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Organic dyes are a promising class of photoredox catalysts and offer a meaningful alternative to broadly applied Ru and Ir complexes. We found that porphyrins with tuned physicochemical properties, by tailoring various substituents at the periphery of the
- Rybicka-Jasińska, Katarzyna,K?nig, Burkhard,Gryko, Dorota
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supporting information
p. 2104 - 2107
(2017/04/24)
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- Modular Construction of Fluoroarenes from a New Difluorinated Building Block by Cross-Coupling/Electrocyclisation/Dehydrofluorination Reactions
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Palladium-catalysed coupling reactions based on a novel and easy-to-synthesise difluorinated organotrifluoroborate were used to assemble precursors to 6π-electrocyclisations of three different types. Electrocyclisations took place at temperatures between 90 and 240 °C, depending on the central component of the π-system; nonaromatic trienes were most reactive, but even systems that required the temporary dearomatisation of two arenyl subunits underwent electrocyclisation, albeit at elevated temperatures. Photochemical conditions were effective for these more demanding reactions. The package of methods delivered a structurally diverse set of fluorinated arenes, spanning a 20 kcal mol?1range of reactivity, by a flexible route.
- Percy, Jonathan M.,Emerson, Helena,Fyfe, James W. B.,Kennedy, Alan R.,Maciuk, Sergej,Orr, David,Rathouská, Lucie,Redmond, Joanna M.,Wilson, Peter G.
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supporting information
p. 12166 - 12175
(2016/08/16)
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- Polyaniline-Induced C-H Arylation of Arenes with Arenediazonium Salts
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A reduced form of polyaniline has been shown to induce direct arylation of an arenediazonium salt with an arene (Gomberg-Bachmann reaction) to give the cross-coupling product in moderate to good yields under mild conditions. Various arenediazonium salts and arenes, including heteroarenes such as furans, thiophenes, and pyrroles, are employed for the reaction. The most favorable combination of substrates is an electron-poor arenediazonium salt with an electron-rich heteroarene. Investigation of the mechanism by reactions with radical scavengers and experiments on kinetic isotope effects indicated the occurrence of a radical chain reaction initiated by one-electron reduction of an arenediazonium salt by the polyaniline. Only 1 mol % (based on aniline tetramer) of the polyaniline is required for the cross-coupling reaction to occur. This reaction proceeds under metal-free conditions and with no need for photonic activation.
- Amaya, Toru,Hata, Dai,Moriuchi, Toshiyuki,Hirao, Toshikazu
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p. 16427 - 16433
(2015/11/10)
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- AgONO-Assisted Direct C-H Arylation of Heteroarenes with Anilines
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A novel copper-catalyzed C-H arylation of heteroarenes with anilines by an in situ diazonium reaction is established by using silver nitrite (AgONO) as an unconventional nitrosating reagent under acid-free conditions. It provides a complementary approach for the C-H arylation of electron-rich heteroarenes with aromatic amines affording a variety of heterobiaryls in moderate to good yields.
- Gowrisankar, Saravanan,Seayad, Jayasree
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supporting information
p. 12754 - 12758
(2015/03/30)
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- Gold(III) porphyrin-catalyzed cycloisomerization of allenones
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Gold(III) porphyrin-catalyzed cycloisomerization of allenones gave the corresponding furans in good to excellent yields (up to 98%) and with quantitative substrate conversions. By recovering the Au(III) catalyst, a recyclable catalytic system is developed with over 8300 product turnovers attained for the cycloisomerization of 1-phenyl-buta-2,3-dien-1-one. The versatility of the gold(III) porphyrin catalyst was exemplified by its application to the hydroamination and hydration of phenylacetylene in 73% and 87% yield, respectively.
- Zhou, Cong-Ying,Chan, Philip Wai Hong,Che, Chi-Ming
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p. 325 - 328
(2007/10/03)
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- A straightforward anionic coupling for the synthesis of ortho-bromobiaryls
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Non-catalyzed anionic coupling of aryllithiums with 1,2-dibromobenzene gives straightforward access to valuable ortho-bromobiaryls.
- Becht, Jean-Michel,Ngouela, Silvère,Wagner, Alain,Mioskowski, Charles
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p. 6853 - 6857
(2007/10/03)
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- Generation of aryl radicals from arylboronic acids by manganese(III) acetate: Synthesis of biaryls and heterobiaryls
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The efficient generation of aryl radicals from arylboronic acids by manganese(III) acetate is described. In aromatic solvents, in situ generated aryl radicals afford the corresponding biaryls in very good yields. This method works selectively, and yields
- Demir, Ayhan S.,Reis, Oemer,Emrullahoglu, Mustafa
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p. 578 - 580
(2007/10/03)
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- Manganese(III) acetate-mediated oxidative coupling of phenylhydrazines with furan and thiophene: A novel method for hetero biaryl coupling
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A convenient new method for the arylation of furan and thiophene with arylhydrazine and manganese(III) acetate is described. Oxidation of arylhydrazines with Mn(III) acetate in furan or thiophene affords the corresponding 2-aryl-substituted furans and thiophenes in good yield using commercially available materials; access to 2-substituted heterobiaryls works selectively, and coupling occurs with loss of the hydrazine moiety.
- Demir, Ayhan S.,Reis, ?mer,Emrullaho?lu, Mustafa
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p. 8055 - 8058
(2007/10/03)
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