- One-pot synthesis of new aza- and diaza-aminophenanthrenes
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The synthesis of a series of benzo(iso)quinoline and phenanthroline derivatives has been achieved using an efficient one-pot procedure. It proceeds through a Suzuki-Miyaura cross-coupling followed by a Dieckmann-Thorpe ring closure under microwave irradia
- Rochais, Christophe,Yougnia, Rodrigue,Cailly, Thomas,Sopková-De Oliveira Santos, Jana,Rault, Sylvain,Dallemagne, Patrick
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- Palladium-catalyzed borylation of aryl bromides and chlorides using phosphatrioxa-adamantane ligands
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Catalysts based on the combination of Pd(OAc)2 and the electron-deficient phosphatrioxa-adamantane ligands are described for borylation of aryl bromides and chlorides. Catalytic evaluation of a small library of phosphatrioxa-adamantane ligands provided some insights on the preferred ligand steric profile for borylation reactions. The corresponding aryl boronate esters were accessed under mild conditions (25–70 °C) and isolated in high yields (up to 96%).
- Lamola, Jairus L.,Moshapo, Paseka T.,Holzapfel, Cedric W.,Christopher Maumela, Munaka
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supporting information
(2021/12/13)
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- Improvement in the Palladium-Catalyzed Miyaura Borylation Reaction by Optimization of the Base: Scope and Mechanistic Study
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Aryl boronic acids and esters are important building blocks in API synthesis. The palladium-catalyzed Suzuki-Miyaura borylation is the most common method for their preparation. This paper describes an improvement of the current reaction conditions. By using lipophilic bases such as potassium 2-ethyl hexanoate, the borylation reaction could be achieved at 35 °C in less than 2 h with very low palladium loading (0.5 mol %). A preliminary mechanistic study shows a hitherto unrecognized inhibitory effect by the carboxylate anion on the catalytic cycle, whereas 2-ethyl hexanoate minimizes this inhibitory effect. This improved methodology enables borylation of a wide range of substrates under mild conditions.
- Barroso, Santiago,Joksch, Markus,Puylaert, Pim,Tin, Sergey,Bell, Stephen J.,Donnellan, Luke,Duguid, Stewart,Muir, Colin,Zhao, Peichao,Farina, Vittorio,Tran, Duc N.,De Vries, Johannes G.
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supporting information
p. 103 - 109
(2020/12/22)
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- Unveiling Extreme Photoreduction Potentials of Donor-Acceptor Cyanoarenes to Access Aryl Radicals from Aryl Chlorides
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Since the seminal work of Zhang in 2016, donor-acceptor cyanoarene-based fluorophores, such as 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN), have been widely applied in photoredox catalysis and used as excellent metal-free alternatives to noble metal Ir- and Ru-based photocatalysts. However, all the reported photoredox reactions involving this chromophore family are based on harnessing the energy from a single visible light photon, with a limited range of redox potentials from -1.92 to +1.79 V vs SCE. Here, we document the unprecedented discovery that this family of fluorophores can undergo consecutive photoinduced electron transfer (ConPET) to achieve very high reduction potentials. One of the newly synthesized catalysts, 2,4,5-tri(9H-carbazol-9-yl)-6-(ethyl(phenyl)amino)isophthalonitrile (3CzEPAIPN), possesses a long-lived (12.95 ns) excited radical anion form, 3CzEPAIPN?-*, which can be used to activate reductively recalcitrant aryl chlorides (Ered ≈ -1.9 to -2.9 V vs SCE) under mild conditions. The resultant aryl radicals can be engaged in synthetically valuable aromatic C-B, C-P, and C-C bond formation to furnish arylboronates, arylphosphonium salts, arylphosphonates, and spirocyclic cyclohexadienes.
- Cao, Jilei,Tang, Xinxin,Toh, Ren Wei,Wang, Han,Wu, Jie,Wu, Xiangyang,Xu, Jinhui,Yang, Xiaona,Yeow, Edwin K. L.,Zhou, Rong
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supporting information
p. 13266 - 13273
(2021/09/07)
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- peri-Xanthenoxanthene (PXX): a Versatile Organic Photocatalyst in Organic Synthesis
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Recent years have witnessed a continuous development of photocatalysts to satisfy the growing demand of photophysical and redox properties in photoredox catalysis, with complex structures or alternative strategies devised to access highly reducing or oxidising systems. We report herein the use of peri-xanthenoxanthene (PXX), a simple and inexpensive dye, as an efficient photocatalyst. Its highly reducing excited state allows activation of a wide range of substrates, thus triggering useful radical reactions. Benchmark transformations such as the addition of organic radicals, generated by photoreduction of organic halides, to radical traps are initially demonstrated. More complex dual catalytic manifolds are also shown to be accessible: the β-arylation of cyclic ketones is successful when using a secondary amine as organocatalyst, while cross-coupling reactions of aryl halides with amines and thiols are obtained when using a Ni co-catalyst. Application to the efficient two-step synthesis of the expensive fluoro-tetrahydro-1H-pyrido[4,3-b]indole, a crucial synthetic intermediate for the investigational drug setipiprant, has been also demonstrated. (Figure presented.).
- Pezzetta, Cristofer,Folli, Andrea,Matuszewska, Oliwia,Murphy, Damien,Davidson, Robert W. M.,Bonifazi, Davide
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supporting information
p. 4740 - 4753
(2021/04/09)
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- Preparation method of o-nitrile phenylboronic acid-1, 3-propylene glycol ester
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The invention discloses a preparation method of o-nitrile phenylboronic acid-1, 3-propylene glycol ester, which belongs to the technical field of organic boric acid chemistry. The method comprises thefollowing steps of starting from o-bromobenzonitrile, carrying out a one-pot reaction with borate/n-butyllithium or metal lithium/boron halide amine, after the reaction is detected to be finished, carrying out acidolysis to obtain 2-nitrile phenylboronic acid, or directly filtering, distilling, adding 1, 3-propylene glycol to form ester, pulping, and purifying to obtain the o-nitrile phenylboronic acid-1, 3-propylene glycol ester. The key point of the process is that the reaction liquid is added into the acid water for quenching after the reaction is finished, so that the condition that the acid water is added into a reaction system to be subjected to an alkaline environment first and then to an acid environment is avoided, the yield is kept stable in different amplification stages, and the process has an industrial amplification prospect. And corresponding boric acid ester can be smoothly obtained by replacing propylene glycol with other glycols.
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Paragraph 0038-0039
(2021/01/29)
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- Facile and economical Miyaura borylation and one-pot Suzuki–Miyaura cross-coupling reaction
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Facile and economical method for Miyaura borylation reaction between B2pin2 and aryl bromides is reported. The catalytic system containing 2 mol% PdCl2(PPh3)2 and KOAc serves to enable borylations to occur under solvent-free and atmospheric conditions. The developed protocol can be applied to synthesize symmetrical and unsymmetrical biaryls via one-pot two-step Suzuki–Miyaura cross-coupling reaction and also offers the up-scalability.
- Boontiem, Phongsakorn,Kiatisevi, Supavadee
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- Controllable factors of supported IR complex catalysis for aromatic C?H borylation
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We have developed a catalyst in which an Ir complex and organic functionalities are coimmobilized on the silica surface. The catalytic activity for aromatic C?H borylation was significantly affected by (i) the linker length of the Ir?bipyridine complex, (ii) the coimmobilized organic functionality, and (iii) the substituents on the aromatic substrate compounds. The fine-tuned supported catalyst showed higher activity than the homogeneous Ir?bipyridine complex when using a specific substrate such as benzonitrile. We elucidated this property by conducting solid-state NMR, FT-IR, XAFS, and in situ FT-IR analysis.
- Chun, Wang-Jae,Maeda, Kyogo,Manaka, Yuichi,Motokura, Ken,Nakajima, Kiyotaka,Satter, Shazia Sharmin,Uemura, Yohei
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p. 14552 - 14559
(2020/12/21)
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- Cleavage of C(aryl)?CH3 Bonds in the Absence of Directing Groups under Transition Metal Free Conditions
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Organic chemists now can construct carbon–carbon σ-bonds selectively and sequentially, whereas methods for the selective cleavage of carbon–carbon σ-bonds, especially for unreactive hydrocarbons, remain limited. Activation by ring strain, directing groups, or in the presence of a carbonyl or a cyano group is usually required. In this work, by using a sequential strategy site-selective cleavage and borylation of C(aryl)?CH3 bonds has been developed under directing group free and transition metal free conditions. Methyl groups of various arenes are selectively cleaved and replaced by boryl groups. Mechanistic analysis suggests that it proceeds by a sequential intermolecular oxidation and coupling of a transient aryl radical, generated by radical decarboxylation, involving a pyridine-stabilized persistent boryl radical.
- Dai, Peng-Fei,Ning, Xiao-Shan,Wang, Hua,Cui, Xian-Chao,Liu, Jie,Qu, Jian-Ping,Kang, Yan-Biao
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supporting information
p. 5392 - 5395
(2019/03/29)
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- Photoinduced Miyaura Borylation by a Rare-Earth-Metal Photoreductant: The Hexachlorocerate(III) Anion
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The first photoinduced carbon(sp2)–heteroatom bond forming reaction by a rare-earth-metal photoreductant, a Miyaura borylation, has been achieved. This simple, scalable, and novel borylation method that makes use of the hexachlorocerate(III) anion ([CeIIICl6]3?, derived from CeCl3) has a broad substrate scope and functional-group tolerance and can be conducted at room temperature. Combined with Suzuki–Miyaura cross-coupling, the method is applicable to the synthesis of various biaryl products, including through the use of aryl chloride substrates.
- Qiao, Yusen,Yang, Qiaomu,Schelter, Eric J.
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supporting information
p. 10999 - 11003
(2018/07/31)
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- Titanocene-Mediated Dinitrile Coupling: A Divergent Route to Nitrogen-Containing Polycyclic Aromatic Hydrocarbons
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A general synthetic strategy for the construction of large, nitrogen-containing polycyclic aromatic hydrocarbons (PAHs) is reported. The strategy involves two key steps: (1) a titanocene-mediated reductive cyclization of an oligo(dinitrile) precursor to form a PAH appended with di(aza)titanacyclopentadiene functionality; (2) a divergent titanocene transfer reaction, which allows final-step installation of one or more o-quinone, diazole, or pyrazine units into the PAH framework. The new methodology enables rational, late-stage control of HOMO and LUMO energy levels and thus photophysical and electrochemical properties, as revealed by UV/vis and fluorescence spectroscopy, cyclic voltammetry, and DFT calculations. More generally, this contribution presents the first productive use of di(aza)metallacyclopentadiene intermediates in organic synthesis, including the first formal [2 + 2 + 2] reaction to form a pyrazine ring.
- Kiel, Gavin R.,Samkian, Adrian E.,Nicolay, Amélie,Witzke, Ryan J.,Tilley, T. Don
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supporting information
p. 2450 - 2454
(2018/02/28)
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- Radical Metal-Free Borylation of Aryl Iodides
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A simple metal-free borylation of aryl iodides mediated by a fluoride sp 2 -sp 3 diboron adduct is described. The reaction conditions are compatible with various functional groups. Electronic effects of substituents do not affect the borylation while steric hindrance does. The reaction proceeds via a radical mechanism in which pyridine serves to stabilize the boryl radicals, generated in situ.
- Pinet, Sandra,Liautard, Virginie,Debiais, Mégane,Pucheault, Mathieu
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p. 4759 - 4768
(2017/10/03)
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- Miyaura Borylation and One-Pot Two-Step Homocoupling of Aryl Chlorides and Bromides under Solvent-Free Conditions
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Solvent-free protocols for Miyaura borylation and the one-pot, two-step homocoupling of aryl halides are reported for the first time. Bis(dibenzylideneacetone)palladium(0) [Pd(dba)2] is an optimal source of palladium for Miyaura borylation, while for one-pot two-step homocoupling palladium(II) acetate [Pd(OAc)2] gives highest yields. Aryl bromides are coupled most efficiently using the DPEphos ligand. Chlorides are coupled using XPhos. The developed protocols are robust, versatile and easily reproducible on a large scale.
- Dzhevakov, Pavel B.,Topchiy, Maxim A.,Zharkova, Daria A.,Morozov, Oleg S.,Asachenko, Andrey F.,Nechaev, Mikhail S.
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p. 977 - 983
(2016/04/05)
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- SiliaCat diphenylphosphine palladium(II) catalyzed borylation of aryl halides
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We investigate the heterogeneously catalyzed direct synthesis of boronic acid pinacol esters using a wide range of aryl chlorides, bromides, and iodides, and bis(pinacolato)diboron as the borylating agent over the sol-gel entrapped SiliaCat diphenylphosphine palladium(II) catalyst. Optimization of the reaction conditions, scale-up of the optimized process, and analysis of palladium leaching enabled us to establish a new selective route for direct access to a diverse set of boronic acid pinacol esters. Clean borylation for scale-up: With the easy access and broad availability of diverse borylated species, the Suzuki-Miyaura reaction has become routine in industry and in research labs. We report a new selective route for direct access to a diverse set of boronic acid pinacol esters over the sol-gel entrapped SiliaCat diphenylphosphine palladium(II) catalyst that can be easily scaled-up.
- Pandarus, Valerica,Marion, Olivier,Gingras, Genevieve,Beland, Francois,Ciriminna, Rosaria,Pagliaro, Mario
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p. 1340 - 1348
(2014/05/20)
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- Synthesis of pinacol arylboronates from aromatic amines: A metal-free transformation
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A metal-free borylation process based on Sandmeyer-type transformation using arylamines derivatives as the substrates has been developed. Through optimization of the reaction conditions, this novel conversion can be successfully applied to a wide range of aromatic amines, affording borylation products in moderate to good yields. Various functionalized arylboronates, which are difficult to access by other methods, can be easily obtained with this metal-free transformation. Moreover, this transformation can be followed by Suzuki-Miyaura cross-coupling without purification of the borylation products, which enhances the practical usefulness of this method. A possible reaction mechanism involving radical species has been proposed.
- Qiu, Di,Jin, Liang,Zheng, Zhitong,Meng, He,Mo, Fanyang,Wang, Xi,Zhang, Yan,Wang, Jianbo
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p. 1923 - 1933
(2013/03/29)
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- Flow synthesis of arylboronic esters bearing electrophilic functional groups and space integration with Suzuki-Miyaura coupling without intentionally added base
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We found that an integrated flow microreactor system enables the preparation of boronic esters bearing electrophilic functional groups using organolithium chemistry and that it allows for their use in Suzuki-Miyaura cross-coupling without intentionally added base. Based on this method, cross-coupling of two aryl halides bearing electrophilic functional groups was accomplished to obtain the corresponding biaryl compounds in one flow.
- Nagaki, Aiichiro,Moriwaki, Yuya,Yoshida, Jun-Ichi
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supporting information
p. 11211 - 11213
(2013/01/15)
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- Synthesis of biaryls through a one-pot tandem borylation/Suzuki-Miyaura cross-coupling reaction catalyzed by a palladacycle
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The tricyclohexylphosphane adduct of cyclopalladated ferrocenylimine I exhibited high catalytic activity in the one-pot borylation/Suzuki-Miyaura coupling (BSC) reaction with low catalyst loading (2 mol-%). Various biaryls were obtained in good to excellent yields for 37 examples. This process was applied to aryl and heteroaryl halides (Br and Cl) containing a variety of functional groups and did not require an excess amount of phosphane ligand and the addition of the palladium catalyst in the second step. Cyclopalladated ferrocenylimine I exhibited high catalytic activity in the borylation/Suzuki- Miyaura coupling (BSC) reaction with low catalyst loading. Various unsymmetrical biaryls were obtained ingood to excellent yields in one pot. This protocol was applied to aryl and heteroaryl halides (Br and Cl) containing a variety of functional groups without adding catalyst in the second step. Copyright
- Wang, Lianhui,Cui, Xiuling,Li, Jingya,Wu, Yusheng,Zhu, Zhiwu,Wu, Yangjie
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experimental part
p. 595 - 603
(2012/03/09)
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- General method for the synthesis of substituted phenanthridin-6(5H)-ones using a KOH-mediated anionic ring closure as the key step
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Substituted phenanthridin-6(5H)-ones were obtained in a two-step procedure involving a Suzuki cross-coupling reaction followed by a KOH-mediated anionic ring closure. The influence of the nature and the position of the substituents on the cyclization step were studied. This methodology offers a general and practical route to diversely substituted phenanthridin-6(5H)-ones.
- Dubost, Emmanuelle,Magnelli, Rosa,Cailly, Thomas,Legay, Rémi,Fabis, Frédéric,Rault, Sylvain
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experimental part
p. 5008 - 5016
(2010/08/13)
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- Cyclopalladated ferrocenylimine as efficient catalyst for the syntheses of arylboronate esters
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The cyclopalladated ferrocenylimine I and its phosphine adducts IIa-f were prepared and evaluated in the borylation of aryl halides. The tricyclohexylphosphine adduct IIb exhibited highly catalytic activity for the coupling of aryl and heteroaryl bromides containing various functional groups with low catalyst loading (2 mol%). Aryl and heteroaryl chlorides were smoothly converted into the corresponding boronates in the presence of the monophosphinobiaryl ligand (XPhos) adduct IIf. It was proposed that palladacycle was only a reservoir of the catalytically active species from the investigation on the reaction mechanism.
- Wang, Lianhui,Li, Jingya,Cui, Xiuling,Wu, Yusheng,Zhu, Zhiwu,Wu, Yangjie
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experimental part
p. 2002 - 2010
(2010/10/19)
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- A novel transmetallation of arylzinc species into arylboronates from aryl halides in a barbier procedure
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A variety of functionalized arylboronates are obtained in moderate to excellent yield by a one-step chemical procedure from the corresponding halides and a haloboronic ester via an intermediate arylzinc species. The Royal Society of Chemistry.
- Claudel, Stephanie,Gosmini, Corinne,Paris, Jean Marc,Perichon, Jacques
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p. 3667 - 3669
(2008/03/14)
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- Transition metal complexes of N-heterocyclic carbenes, method of preparation and use in transition metal catalyzed organic transformations
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The present invention relates to catalysts of transition metal complexes of N-heterocyclic carbenes, their methods of preparation and their use in chemical synthesis. The synthesis, ease-of-use, and activity of the compounds of the present invention are substantial improvements over in situ catalyst generation. Further, the transition metal complexes of N-heterocyclic carbenes of the present invention may be used as precatalysts in metal-catalyzed cross-coupling reactions.
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Page/Page column 15; 25
(2010/11/26)
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- Process for producing cyano substituted arene boranes and compounds
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A process for producing cyano substituted arene boranes is described. The compounds are useful intermediates to pharmaceutical compounds using the cyano group as a reactant.
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Page/Page column 15
(2008/06/13)
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- Sterically directed functionalization of aromatic C-H bonds: Selective borylation ortho to cyano groups in arenes and heterocycles
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Ir-catalyzed borylations of 4-substituted benzonitriles are described. In contrast to electrophilic aromatic substitutions and directed ortho metalations, C-H activation/borylation enables functionalization at the 2-position, adjacent to the cyano group, when the 4-subsitutent is larger than cyano. When an excess of borane reagent is used, diborylation can be achieved with a single regioisomer being formed in certain cases. Extension of sterically directed borylation to cyano-substituted, five- and six-membered ring heterocycles is also reported.
- Chotana, Ghayoor A.,Rak, Michael A.,Smith, Milton R.
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p. 10539 - 10544
(2007/10/03)
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- IMIDAZO-TRIAZINE DERIVATIVES AS LIGANDS FOR GABA RECEPTORS
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A class of imidazo[1,2b][1,2,4]triazine derivatives, substituted at the 7-position by an optionally substituted five-membered or six-membered heteroaromatic ring, being selective ligands for GABAA receptors, in particular having good affinity for the α2 a
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Page/Page column 34
(2010/02/07)
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- Investigations into the Suzuki-Miyaura coupling aiming at multikilogram synthesis of E2040 using (o-cyanophenyl)boronic esters
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The Suzuki-Miyaura cross-coupling reaction between 1-{3-bromo-4-chloro-5-[1-(R)-fluoropropyl]}phenylpiperazine ((R)-1b) and thermally unstable (0-cyanophenyl)boronic ester 6b in the presence of dichlorobis(triphenylphosphine)palladium and potassium phosph
- Urawa, Yoshio,Naka, Hiroyuki,Miyazawa, Mamoru,Souda, Shigeru,Ogura, Katsuyuki
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p. 269 - 278
(2007/10/03)
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- Synthesis of pinacol arylboronates via cross-coupling reaction of bis(pinacolato)diboron with chloroarenes catalyzed by palladium(0)-tricyclohexylphosphine complexes
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The cross-coupling reaction of bis(pinacolato)diboron with chloroarenes to yield pinacol arylboronates was carried out in 1,4-dioxane at 80°C in the presence of KOAc (1.5 equiv.) and Pd(dba)2/2.4PCy3 (3-6 mol%). The catalyst was also effective to carry out analogous coupling with aryl bromides or triflates under milder conditions than those of the previous procedures catalyzed by PdCl2(dppf) in DMSO.
- Ishiyama, Tatsuo,Ishida, Kousaku,Miyaura, Norio
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p. 9813 - 9816
(2007/10/03)
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