- Palladium Complexes with Phenoxy- And Amidate-Functionalized N-Heterocyclic Carbene Ligands Based on 3-Phenylimidazo[1,5- a]pyridine: Synthesis and Catalytic Application in Mizoroki-Heck Coupling Reactions with Ortho-Substituted Aryl Chlorides
-
Mononuclear and tetranuclear palladium complexes with functionalized "abnormal"N-heterocyclic carbene (aNHC) ligands based on 3-phenylimidazo[1,5-a]pyridine were synthesized. All of the new complexes were structurally characterized by single-crystal X-ray diffraction studies. The new complexes were applied in the Mizoroki-Heck coupling reaction of aryl chlorides with alkenes in neat n-tetrabutylammonium bromide (TBAB). The mononuclear palladium complex with a tridentate phenoxy- and amidate-functionalized aNHC ligand displayed activity superior to that of the palladium complex with a bidentate amidate-functionalized aNHC ligand. The new tetranuclear complex with the tridentate ligand displayed the best activities, capable of the activation of deactivated aryl chlorides as substrates with a low Pd atom loading. Even challenging sterically demanding ortho-substituted aryl chlorides were successfully utilized as substrates. The studies revealed that the robustness of the catalyst precursor is crucial in delivering high catalytic activities. Also, the promising use of tetranuclear palladium complexes with functionalized aNHC ligands as the catalyst precursors in the Mizoroki-Heck coupling reaction in neat TBAB was demonstrated.
- Hung, Cheng-Hau,Zheng, Wei-Yuan,Lee, Hon Man
-
p. 702 - 713
(2021/04/02)
-
- Synthesis of Indoles by Reductive Cyclization of Nitro Compounds Using Formate Esters as CO Surrogates
-
Alkyl and aryl formate esters were evaluated as CO sources in the Pd- and Pd/Ru-catalyzed reductive cyclization of 2-nitrostyrenes to give indoles. Whereas the use of alkyl formates requires the presence of a ruthenium catalyst such as Ru3(CO)12, the reaction with phenyl formate can be performed by using a Pd/phenanthroline complex alone. Phenyl formate was found to be the most effective CO source and the desired products were obtained in excellent yields, often higher than those previously reported using pressurized CO. The reaction tolerates many functional groups, including sensitive ones like a free aldehydic group or a pendant pyrrole. Detailed experiments and kinetic studies allow to conclude that the activation of phenyl formate is base-catalyzed and that the metal doesn't play a role in the decarbonylation step. The reactions can be performed in a single thick-walled glass tube with as little as 0.2 mol-% palladium catalyst and even on a 2 g scale. The same protocol can be extended to other nitro compounds, affording different heterocycles.
- Ahmed Fouad, Manar,Ferretti, Francesco,Formenti, Dario,Milani, Fabio,Ragaini, Fabio
-
supporting information
p. 4876 - 4894
(2021/09/20)
-
- Counterion Control of t-BuO-Mediated Single Electron Transfer to Nitrostilbenes to Construct N-Hydroxyindoles or Oxindoles
-
tert-Butoxide unlocks new reactivity patterns embedded in nitroarenes. Exposure of nitrostilbenes to sodium tert-butoxide was found to produce N-hydroxyindoles at room temperature without an additive. Changing the counterion to potassium changed the reaction outcome to yield solely oxindoles through an unprecedented dioxygen-transfer reaction followed by a 1,2-phenyl migration. Mechanistic experiments established that these reactions proceed via radical intermediates and suggest that counterion coordination controls whether an oxindole or N-hydroxyindole product is formed.
- Driver, Tom G.,Sung, Siyoung,Wink, Donald J.,Zadrozny, Joseph M.,Zhao, Yingwei,Zhu, Haoran
-
supporting information
p. 19207 - 19213
(2021/08/09)
-
- Wittig Olefination Using Phosphonium Ion-Pair Reagents Incorporating an Endogenous Base
-
Despite common perception, the use of strong bases in Wittig chemistry is utterly unnecessary: we report a series of novel ion-pair phosphonium carboxylate reagents which are essentially "storable ylides". These reagents are straightforwardly prepared in excellent yields, and their fluxional nature permits clean olefination of a broad range of aldehydes and even hemiacetals.
- Vetter, Anna C.,Gilheany, Declan G.,Nikitin, Kirill
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p. 1457 - 1462
(2021/03/08)
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- Palladium-Based Catalysts Supported by Unsymmetrical XYC–1 Type Pincer Ligands: C5 Arylation of Imidazoles and Synthesis of Octinoxate Utilizing the Mizoroki–Heck Reaction
-
A series of new unsymmetrical (XYC–1 type) palladacycles (C1–C4) were designed and synthesized with simple anchoring ligands L1–4H (L1H = 2-((2-(4-methoxybenzylidene)-1-phenylhydrazinyl)methyl)pyridine, L2H = N,N-dimethyl-4-((2-phenyl-2-(pyridin-2-ylmethyl)hydrazono)methyl)aniline, L3H = N,N-diethyl-4-((2-phenyl-2-(pyridin-2-ylmethyl)hydrazono)methyl) aniline and L4H = 4-(4-((2-phenyl-2-(pyridin-2-ylmethyl)hydrazono) methyl)phenyl)morpholine H = dissociable proton). Molecular structure of catalysts (C1–C4) were further established by single X-ray crystallographic studies. The catalytic performance of palladacycles (C1–C4) was explored with the direct Csp2–H arylation of imidazoles with aryl halide derivatives. These palladacycles were also applied for investigating of Mizoroki–Heck reactions with aryl halides and acrylate derivatives. During catalytic cycle in situ generated Pd(0) nanoparticles were characterized by XPS, SEM and TEM analysis and possible reaction pathways were proposed. The catalyst was employed as a pre-catalyst for the gram-scale synthesis of octinoxate, which is utilized as a UV-B sunscreen agent.
- Maji, Ankur,Singh, Ovender,Singh, Sain,Mohanty, Aurobinda,Maji, Pradip K.,Ghosh, Kaushik
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p. 1596 - 1611
(2020/04/29)
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- 1,3-Diphenyldisiloxane Enables Additive-Free Redox Recycling Reactions and Catalysis with Triphenylphosphine
-
The recently reported chemoselective reduction of phosphine oxides with 1,3-diphenyldisiloxane (DPDS) has opened up the possibility of additive-free phosphine oxide reductions in catalytic systems. Herein we disclose the use of this new reducing agent as an enabler of phosphorus redox recycling in Wittig, Staudinger, and alcohol substitution reactions. DPDS was successfully utilized in ambient-temperature additive-free redox recycling variants of the Wittig olefination, Appel halogenation, and Staudinger reduction. Triphenylphosphine-promoted catalytic recycling reactions were also facilitated by DPDS. Additive-free triphenylphosphine-promoted catalytic Staudinger reductions could even be performed at ambient temperature due to the rapid nature of phosphinimine reduction, for which we characterized kinetic and thermodynamic parameters. These results demonstrate the utility of DPDS as an excellent reducing agent for the development of phosphorus redox recycling reactions.
- Buonomo, Joseph A.,Cole, Malcolm S.,Eiden, Carter G.,Aldrich, Courtney C.
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p. 3583 - 3594
(2020/09/15)
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- Pd-Catalyzed Reductive Cyclization of Nitroarenes with CO2 as the CO Source
-
A reductive amination process that constructs indoles, carbazoles or benzimidazoles from nitroarenes – irrespective of their electronic or steric nature – was developed that uses CO2 as the source of CO. The process is robust, tolerating common gaseous components of flue gas (H2S, SO2, NO and H2O) without adversely affecting the reductive cyclization.
- Guan, Xinyu,Zhu, Haoran,Zhao, Yingwei,Driver, Tom G.
-
supporting information
p. 57 - 60
(2019/12/11)
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- Highly active homoleptic nickel(II) bis-N-heterocyclic carbene catalyst for Suzuki–Miyaura and Heck cross-coupling reactions
-
New homoleptic nickel(II) biscarbene complex was synthesized and structurally characterized. The complex depicted the excellent catalytic activities with only 3 mol% catalyst loading along with wide substrate scope for the Suzuki–Miyaura cross-coupling reactions (twenty six examples) and Heck coupling reactions (eighteen examples).
- Nirmala, Muthukumaran,Arruri, Sathyanarayana,Vaddamanu, Moulali,Karupnaswamy, Ramesh,Mannarsamy, Maruthupandi,Adinarayana, Mannem,Ganesan, Prabusankar
-
supporting information
p. 125 - 134
(2018/11/23)
-
- CuH-Catalyzed Synthesis of 3-Hydroxyindolines and 2-Aryl-3H-indol-3-ones from o-Alkynylnitroarenes, Using Nitro as Both the Nitrogen and Oxygen Source
-
CuH-catalyzed diasterospecific synthesis of 3-hydroxyindolines and 2-aryl-3H-indol-3-ones have been developed from o-alkynylnitroarenes in the presence of hydrosilane as the reductant. The protocol employs nitro as both nitrogen and oxygen sources for the
- Peng, Hui,Ma, Jinhui,Duan, Lingfei,Zhang, Guangwen,Yin, Biaolin
-
supporting information
p. 6194 - 6198
(2019/08/20)
-
- Metal-free deoxygenation and reductive disilylation of nitroarenes by organosilicon reducing reagents
-
A metal-free deoxygenation and reductive disilylation of nitroarenes was achieved using N,N’-bis(trime-thylsilyl)-4,4’-bipyridinylidene (1) under mild and neutral reaction conditions, and a broad functional group tolerance was possible in this reaction. Mono-deoxygenation, giving a synthetically valuable N,O-bis(trimethylsilyl)phe-nylhydroxylamine (7a) as a readily available and safe phenylnitrene source from nitrobenzene, and double-deoxy-genation, giving N,N-bis(trimethylsilyl)anilines 8, were easily controlled by varying the amounts of 1 and reaction temperature as well as adding dibenzothiophene (DBTP). Reaction of 2-arylnitrobenzenes with 1 resulted in the formation of the corresponding carbazoles 14 via in situ-gen-erated phenylnitrene species derived by thermolysis of N,O-bis(trimethylsilyl)phenylhydroxylamines 7, followed by their subsequent intramolecular C H insertion. In addition, the intramolecular N N coupling reaction proceeded in the reduction of 2,2’-dinitrobiphenyl derivatives by 1, giving the corresponding benzo[c]cinnolines.
- Bhattacharjee, Argha,Hosoya, Hiromu,Ikeda, Hideaki,Nishi, Kohei,Tsurugi, Hayato,Mashima, Kazushi
-
supporting information
p. 11278 - 11282
(2018/10/20)
-
- Efficient nickel(II) naringenin-oxime complex catalyzed Mizoroki-Heck cross-coupling reaction in the presence of hydrazine hydrate
-
A novel nickel(ii) naringenin-oxime complex was designed, synthesized and characterized. Therein, the nickel(ii) naringenin oxime complex as an efficient catalyst was used in Mizoroki-Heck coupling reactions of aryl halides containing electron-rich and electron-deficient substituents with styrene, methyl acrylate and divinylbenzene (DVB), respectively. The reaction proceeded efficiently under alkaline conditions in the presence of 0.30 mol% of the Ni(ii) naringenin oxime complexand N2H4·H2O as the reductant in EtOH at 80 °C, and 32 alkene products were afforded in moderate to excellent yields, containing four new olefins. The new catalytic system not only provided an inexpensive and efficient process with greener conditions, but also broadened the reaction scope.
- Song, Jin-Yi,Liu, Yang,Zhao, Hong-Yan,Han, Hua-Tao,Li, Zhuo-Fei,Guo, Wei-Hao,Chu, Wen-Yi,Sun, Zhi-Zhong
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p. 12288 - 12292
(2017/10/16)
-
- Coupling Radical Homoallylic Expansions with C-C Fragmentations for the Synthesis of Heteroaromatics: Quinolines from Reactions of o-Alkenylarylisonitriles with Aryl, Alkyl, and Perfluoroalkyl Radicals
-
Selective addition of radicals to isonitriles can be harnessed for initiating reaction cascades designed to overcome the stereoelectronic restrictions on homoallylic ring expansion in alkyne reactions and to develop a new general route for the preparation of N-heteroaromatics. This method utilizes alkenes as synthetic equivalents of alkynes by coupling homoallylic ring expansion to yield the formal "6-endo" products with aromatization via stereoelectronically assisted C-C bond scission. Computational analysis of the homoallyic expansion potential energy surface reveals that the indirect 5-exo/3-exo/retro-3-exo path is faster than the direct 6-endo-trig closure, revealing the general exo-preference for the cyclization processes.
- Evoniuk, Christopher J.,Gomes, Gabriel Dos Passos,Ly, Michelle,White, Frankie D.,Alabugin, Igor V.
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p. 4265 - 4278
(2017/04/27)
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- NH2-directed C-H alkenylation of 2-vinylanilines with vinylbenziodoxolones
-
The first directing-group-mediated C-H alkenylation with alkenyl-λ3-iodanes as electrophilic alkene-transfer reagents has been developed. The application of free aromatic amines as challenging but synthetically valuable directing groups in combination with an IrIII catalyst enabled the synthesis of highly desirable 1, 3- dienes in excellent yields of up to 98% with high to perfect (Z, E) stereoselectivity. A broad substrate scope and further synthetic modifications are demonstrated.
- Boelke, Andreas,Caspers, Lucien D.,Nachtsheim, Boris J.
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supporting information
p. 5344 - 5347
(2017/11/07)
-
- Metal-free denitrative arylation of β-nitrostyrenes using benzoyl peroxide: An easy access to: Trans -stilbenes
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A simple, novel and stereoselective synthesis of trans-stilbenes has been described using denitrative arylation of β-nitrostyrenes in the presence of benzoyl peroxide under metal-free conditions. The reaction is assumed to involve homolytic cleavage of benzoyl peroxide followed by decarboxylation to generate a phenyl radical, which brings about ipso-substitution of the nitro group of nitrostyrenes to afford trans-stilbenes.
- Yadav, Arvind Kumar,Singh, Krishna Nand
-
supporting information
p. 14914 - 14917
(2017/12/15)
-
- Synthesis, structure and catalysis of a NHC-Pd(II) complex based on a tetradentate mixed ligand
-
Bis-benzimidazolium salt (S)-2,2′-bis[2′′-(N-picolyl-benzimidazoliumyl)ethoxy]-1,1′-binaphthyl hexafluorophosphate [(S)-LH2]·(PF6)2 and its NHC palladium(ii) complex [(S)-LPd](PF6)2 (1) have been prepared and characterized. Complex 1 is formed by one tetradentate mixed ligand (S)-L and one Pd(ii) ion, in which one 15-membered ring and two 6-membered rings are present. In this complex, intramolecular π-π interactions between naphthalene rings and benzimidazole rings are observed. Additionally, the catalytic activity of complex 1 in three types of C-C coupling reactions (Suzuki-Miyaura, Heck-Mizoroki and Sonogashira reactions) was investigated. The results show that complex 1 is an effective catalyst in these coupling reactions.
- Liu, Qing-Xiang,Cai, Kang-Qing,Zhao, Zhi-Xiang
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p. 85568 - 85578
(2015/11/03)
-
- Coupling cyclizations with fragmentations for the preparation of heteroaromatics: Quinolines from o-alkenyl arylisocyanides and boronic acids
-
Stereoelectronic restrictions on homoallylic ring expansion in alkyne cascades can be overcome by using alkenes as synthetic equivalents of alkynes in reaction cascades that are terminated by C-C bond fragmentation. Implementation of this approach using Mn(iii)-mediated reaction of o-alkenyl isocyanides and boronic acids leads to efficient synthesis of substituted quinolines.
- Evoniuk, Christopher J.,Ly, Michelle,Alabugin, Igor V.
-
supporting information
p. 12831 - 12834
(2015/08/06)
-
- Styrylphenylphthalimides as Novel Transrepression-Selective Liver X Receptor (LXR) Modulators
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Anti-inflammatory effects of liver X receptor (LXR) ligands are thought to be largely due to LXR-mediated transrepression, whereas side effects are caused by activation of LXR-responsive gene expression (transactivation). Therefore, selective LXR modulators that preferentially exhibit transrepression activity should exhibit anti-inflammatory properties with fewer side effects. Here, we synthesized a series of styrylphenylphthalimide analogues and evaluated their structure-activity relationships focusing on LXRs-transactivating-agonistic/antagonistic activities and transrepressional activity. Among the compounds examined, 17l showed potent LXR-transrepressional activity with high selectivity over transactivating activity and did not show characteristic side effects of LXR-transactivating agonists in cells. This representative compound, 17l, was confirmed to have LXR-dependent transrepressional activity and to bind directly to LXRβ. Compound 17l should be useful not only as a chemical tool for studying the biological functions of LXRs transrepression but also as a candidate for a safer agent to treat inflammatory diseases.
- Nomura, Sayaka,Endo-Umeda, Kaori,Aoyama, Atsushi,Makishima, Makoto,Hashimoto, Yuichi,Ishikawa, Minoru
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supporting information
p. 902 - 907
(2015/08/24)
-
- Palladium nanoparticles supported on triazine functionalised mesoporous covalent organic polymers as efficient catalysts for Mizoroki-Heck cross coupling reaction
-
A novel class of mesoporous covalent organic polymer (MCOP) was synthesised by the nucleophilic substitution of cyanuric chloride with 4,4′- dihydroxybiphenyl. The MCOP was fully characterized using powder X-ray diffraction analysis, Fourier transform infrared spectroscopy, 13C-solid state NMR spectroscopy, field emission scanning electron microscopy and thermogravimetric analysis. These nitrogen rich materials act as good supports for palladium nanoparticles (Pd NPs) and exhibit excellent catalytic activity towards Mizoroki-Heck cross coupling between aryl bromides and alkenes. Hot filtration tests demonstrate that the presence of the triazine rings on the polymers is beneficial for enhancing the stability of Pd NPs. The polymers are also cheap, easy to synthesise and can be recycled up to five times with only a minor loss of activity. the Partner Organisations 2014.
- Puthiaraj, Pillaiyar,Pitchumani, Kasi
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p. 4223 - 4233
(2014/10/15)
-
- Palladium(II) tetrakis(4-N,N,N-trimethylammoniumphenylene)porphyrin supported on ion-exchange resins as efficient and reusable catalysts for C-C coupling reactions
-
In this research, the Heck and Suzuki reactions catalyzed by tetrakis(4-N,N,N-trimethylammoniumphenylene)porphyrinatopalladium(II) iodide, [Pd(TTMAPP)]I4, immobilized on ion-exchange resins such as Dowex 50 WX8 and Amberlite IR-120 are reported. In this manner, first, tetrakis(4-N,N-dimethylaminophenylene)porphyrin was converted to tetrakis(4-N,N,N-trimethylammoniumphenylene)porphyrin iodide, [H 2TTMAPP]I4, with methyl iodide. Then this water soluble porphyrin was metalated by palladium(II) chloride and the [Pd(TTMAPP)]I 4 was produced. This cationic palladium porphyrin was immobilized onto the ionic supports via electrostatic interactions. The catalysts, [Pd(TTMAPP)]@Dowex 50 WX8 and [Pd(TTMAPP)]@Amberlit IR-120, were characterized by FT-IR and diffuse reflectance UV-Vis spectroscopic methods, and scanning electron microscopy. These heterogeneous catalysts are thermally stable, oxygen insensitive, phosphine-free, air- and moisture-stable in the C-C coupling reactions and are reusable several times without significant loss of their catalytic activity.
- Sadegh, Faranak,Bagheri, Omid,Moghadam, Majid,Mirkhani, Valiollah,Tangestaninejad, Shahram,Mohammadpoor-Baltork, Iraj
-
-
- Carbon-carbon coupling reactions catalyzed by supported Pd porphyrins
-
The tetrakis(4-N-methylpyridinium)porphyrinatopalladium(II) iodide, [Pd(TMPyP)]I4, supported on Dowex 50WX8 and Amberlite IR-120 ion-exchange resins, was used as heterogeneous, recyclable and active catalyst for the Suzuki-Miyaura and Heck cross-coupling reactions. These catalysts were applied to coupling of various aryl halides with phenylboronic acid and styrene in Suzuki and Heck reactions, respectively, and the corresponding products were obtained in excellent yields and short reaction times. The catalysts could be recovered easily by simple filtration and reused several times without significant loss of their catalytic activity. The catalysts were characterized by diffuse-reflectance UV-visible spectroscopy and scanning electron microscopy, and their stability was confirmed by TGA.
- Bagheri, Omid,Sadegh, Faranak,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj,Safiri, Mahsa
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p. 337 - 346
(2014/05/06)
-
- Highly double selective nitration of nitrostilbenes over zeolite
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A feasible zeolite-assisted ortho C-H nitration of nitrostilbenes has been developed for the first time, which can be used in situ. It uses acetyl nitrate as a mild, easily handled and commercially available nitrating reagent, leading to the synthesis of polynitrostilbenes with double selectivities and in good yields. This journal is the Partner Organisations 2014.
- Xu, Jun-Hui,Wei, Jian-Ping,Hao, Zheng,Ma, Qing-Guo,Peng, Xin-Hua
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supporting information
p. 10710 - 10713
(2014/10/15)
-
- Palladium/copper-catalyzed oxidative arylation of terminal alkenes with aroyl hydrazides
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An unprecedented oxidative arylation reaction of terminal alkenes with simple aroyl hydrazides has been developed under aerobic conditions for the stereoselective synthesis of 1,2-disubstituted alkenes. A range of aroyl hydrazides underwent palladium/copper-catalyzed oxidative Mizoroki-Heck reaction with terminal alkenes open to air in a 1:1 mixture of dimethyl sulfoxide and acetonitrile to give structurally diverse 1,2-disubstituted alkenes in moderate to excellent yields with excellent regio- and E-selectivity. The reaction tolerated a wide variety of functional groups, such as alkoxy, hydroxy, amino, fluoro, chloro, bromo, cyano, nitro, ester, amide, imide, phosphine oxide, and sulfone groups, and, moreover, molecular oxygen and dimethyl sulfoxide were demonstrated to serve as terminal oxidants. This study provides a useful method for the stereoselective synthesis of 1,2-disubstituted alkenes through direct transformation of the vinylic Ci-H bonds in terminal alkenes. Cross-coupling: An oxidative arylation reaction of terminal alkenes with simple aroyl hydrazides has been developed in the presence of a PdCl2/CuI catalyst under aerobic conditions to give a range of structurally diverse 1,2-disubstituted alkenes in moderate to excellent yields with excellent regio- and E-selectivity (see scheme; r.s.=regioselectivity).
- Zhang, Yong-Gang,Liu, Xiang-Lei,He, Zeng-Yang,Li, Xi-Ming,Kang, Hong-Jian,Tian, Shi-Kai
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supporting information
p. 2765 - 2769
(2014/03/21)
-
- Novel isoxazoline ligand with ferrocene backbone: Preparation and application in Heck reaction with water as solvent
-
Two novel isoxazoline N,N-bidentate ligands with ferrocene backbone have been synthesized and employed for the palladium-catalyzed Heck coupling reaction. Among them, 1,3-bis-(5-ferrocenylisoxazoline-3-yl)benzene was found to be thermally stable and a highly effective ligand for Heck coupling reaction in neat water without N2 protection, affording the desired coupling products in good to excellent yield with high diastereoselectivity. The developed catalytic system was also well workable for 1,2-disubstituted alkenes, which were less involved in the Heck reaction for its larger steric hindrance. Copyright
- Yu, Shuyan,Zhang, Zhiqin,Yu, Zhiyu,Shang, Yongjia
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p. 657 - 660
(2014/08/05)
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- Decarboxylative cross-coupling of mesylates catalyzed by copper/palladium systems with customized imidazolyl phosphine ligands
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The activation of the inert C-O bonds in mesylates through the use of a new class of imidazolyl phosphines allows the decarboxylative coupling of aryl mesylates as well as polysubstituted alkenyl mesylates. Variation of the ligands leads to two complementary methods providing the corresponding biaryls and polysubstituted olefins in good yields. Copyright
- Song, Bingrui,Knauber, Thomas,Goo?en, Lukas J.
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p. 2954 - 2958
(2013/04/11)
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- Palladium nanoparticles generated from allylpalladium chloride in situ: A simple and highly efficient catalytic system for Mizoroki-Heck reactions
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The Mizoroki-Heck reactions of aryl halides catalyzed by palladium nanoparticles generated in situ from a simple allyl palladium precursor were investigated in argon. The high turnover numbers of 9,300,000 have been obtained with 4-bromobenzonitrile as substrate and 3500 with 4-nitrochlorobenzene. When the reaction was performed in air, a low yield was given, but it could be improved obviously by addition of PEG-400. The main reason was that inactive Pd(II) species could be rapidly reduced to the active Pd(0) by PEG. In other word, the existence of air and PEG led to a synergistic effect which the oxidation by air prevents the aggregation of Pd NPs and the reduction by PEG maintains the high activity of Pd(0) species.
- Wang, Wei,Yang, Qin,Zhou, Rong,Fu, Hai-Yan,Li, Rui-Xiang,Chen, Hua,Li, Xian-Jun
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experimental part
p. 1 - 5
(2012/01/13)
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- Heck-type reaction of aryldiazonium silica sulfates
-
Aryldiazonium silica sulfates were employed as new and efficient reagents for Heck-type arylation reactions with styrene and methyl acrylate. The reactions were carried out in an organic solvent, in the presence of Pd(OAc)2 as precatalyst without use of base and free ligand. The trans isomers of desired products, methyl cinnamates and stilbenes, were obtained with full conversion. Use of a catalytic amount of Pd(OAc)2 produced the corresponding products in short reaction times and excellent yields. Springer-Verlag 2011.
- Pirisedigh, Azadeh,Zarei, Amin,Seyedjamali, Hojjat,Khazdooz, Leila,Hajipour, Abdol R.
-
experimental part
p. 791 - 795
(2012/09/05)
-
- Microwave-assisted wittig reaction of semistabilized nitro-substituted benzyltriphenyl-phosphorous ylides with aldehydes in phase-transfer conditions
-
We report here a simple entry into the nitrostilbene system in very short reaction times and good yields using the microwave-assisted Wittig reaction in phase-transfer conditions of nitro-substituted benzyltriphenylphosphonium ylides with aldehydes. Taylor & Francis Group, LLC.
- Rodrigues, Tiago,Lopes, Francisca,Moreira, Rui
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experimental part
p. 747 - 755
(2011/12/15)
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- A highly efficient and recyclable fluorous palladium catalyst for Heck reactions in water
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A fluorous nano-palladium catalyst has been synthesized and characterized. The catalyst is highly active for the Heck reaction of aryl halides with substituted styrenes in water under air. The corresponding Heck products were obtained in high yields with good stereoselectivity (E/Z up to 98:2). In addition, the catalyst could be recovered by fluorous liquid-liquid separation and reused four times without significant loss of activity or stereoselectivity. Graphical Abstract: The Heck reaction catalyzed by a new fluorous nano-palladium catalyst in water to afford the products in high yields has been described. The catalyst can be recovered by fluorous liquid-liquid separation and reused for several times without significant loss of activity. [Figure not available: see fulltext.]
- Wan, Li,Cai, Chun
-
experimental part
p. 747 - 750
(2012/06/30)
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- Electrosynthesis of substituted 1H-indoles from o-nitrostyrenes
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A novel procedure has been devised for the synthesis of derivatives of 1H-indole that is based on the direct, room-temperature electrochemical reduction of substituted o-nitrostyrenes at carbon cathodes in N,N-dimethylformamide containing tetramethylammonium tetrafluoroborate as supporting electrolyte and in the presence of a 10-fold molar excess of a proton donor (phenol or methyl 3-oxobutanoate).
- Du, Peng,Brosmer, Jonathan L.,Peters, Dennis G.
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supporting information; experimental part
p. 4072 - 4075
(2011/10/04)
-
- Vinyldisiloxanes: Their synthesis, cross coupling and applications
-
During the studies towards the development of pentafluorophenyldimethylsilanes as a novel organosilicon cross coupling reagent it was revealed that the active silanolate and the corresponding disiloxane formed rapidly under basic conditions. The discovery that disiloxanes are in equilibrium with the silanolate led to the use of disiloxanes as cross coupling partners under fluoride free conditions. Our previous report focused on the synthesis and base induced cross coupling of aryl substituted vinyldisiloxanes with aryl halides; good yields and selectivities were achieved. As a continuation of our research, studies into the factors which influence the successful outcome of the cross coupling reaction with both alkyl and aryl substituted vinyldisiloxanes were examined and a proposed mechanism discussed. Further investigation into expanding the breadth and diversity of substituted vinyldisiloxanes in cross coupling was explored and applied to the synthesis of unsymmetrical trans-stilbenes and cyclic structures containing the trans-alkene architecture.
- Sore, Hannah F.,Boehner, Christine M.,Laraia, Luca,Logoteta, Patrizia,Prestinari, Cora,Scott, Matthew,Williams, Katharine,Galloway, Warren R. J. D.,Spring, David R.
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experimental part
p. 504 - 515
(2011/03/17)
-
- Synthesis and antiplasmodial activity of new indolone N-Oxide derivatives
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A series of 66 new indolone-N-oxide derivatives was synthesized with three different methods. Compounds were evaluated for in vitro activity against CQ-sensitive (3D7), CQ-resistant (FcB1), and CQ and pyrimethamine cross-resistant (K1) strains of Plasmodium falciparum (P.f.), aswell as for cytotoxic concentration (CC50) on MCF7 and KB human tumor cell lines. Compound 26 (5-methoxy-indolone-N-oxide analogue) had the most potent antiplasmodial activity in vitro (50 MCF7/IC50 FcB1: 14623; CC50 KB/IC50 3D7: 198823). In in vivo experiments, compound 1 (dioxymethylene derivatives of the indolone-N-oxide) showed the best antiplasmodial activity against Plasmodium berghei, 62% inhibition of the parasitaemia at 30 mg/kg/day. 2009 American Chemical Society.
- Nepveu, Fran?oise,Kim, Sothea,Boyer, Jeremie,Chatriant, Olivier,Ibrahim, Hany,Reybier, Karine,Monje, Marie-Carmen,Chevalley, Severine,Perio, Pierre,Lajoie, Barbora H.,Bouajila, Jalloul,Deharo, Eric,Sauvain, Michel,Tahar, Rachida,Basco, Leonardo,Pantaleo, Antonella,Turini, Francesco,Arese, Paolo,Valentin, Alexis,Thompson, Eloise,Vivas, Livia,Petit, Serge,Nallet, Jean-Pierre
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experimental part
p. 699 - 714
(2010/07/09)
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- Use of a recyclable poly(N-vinyl carbazole) palladium(II) complex catalyst: Heck cross-coupling reaction under phosphine-free and aerobic conditions
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A novel pathway for cross-coupling reaction of terminal alkenes with aryl halides (Heck cross-coupling) has been described using a new phosphine-free poly(N-vinyl carbazole) anchored palladium(II) complex as catalyst in aerobic conditions. The catalyst was found to be highly active for the couplings of a variety of substituted and non-substituted aryl halides with terminal alkenes and to smoothly afford the corresponding desired products in good to excellent yields. The catalyst can be reused at least six times without noticeable decrease in catalytic activity. Springer Science+Business Media B.V. 2010.
- Islam, Manirul,Mondal, Paramita,Roy, Anupam Singha,Tuhina, Kazi
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experimental part
p. 491 - 499
(2011/11/05)
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- Pd-catalyzed decarboxylative Heck vinylation of 2-nitrobenzoates in the presence of CuF2
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A new protocol for the decarboxylative Heck vinylation of benzoic acids is disclosed. In the presence of a catalyst system generated in situ from Pd(OAc)2 (2 mol %), CuF2 (2 equiv), and benzoquinone (0.5 equiv) in NMP, a wide range of olefins were coupled with various 2-nitrobenzoates at 130 °C with the release of carbon dioxide to afford the corresponding vinyl arenes in good yields.
- Goossen, Lukas J.,Zimmermann, Bettina,Knauber, Thomas
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experimental part
(2010/08/19)
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- Separation of α-glucosidase-inhibitory and liver X receptor-antagonistic activities of phenethylphenyl phthalimide analogs and generation of LXRα-selective antagonists
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Liver X receptor (LXR) α/β dual agonists are candidate medicaments for the treatment of metabolic syndrome, because their biological actions include increasing cholesterol efflux mediated by LXRβ. However, their clinical application is currently limited by their enhancing effect on triglyceride (TG) synthesis mediated by LXRα. Combination of an LXRα-selective antagonist with an LXRα/β dual agonist may overcome this disadvantage. In the present work, structural development studies of phenethylphenyl phthalimide 9, which possesses LXRα/β dual-antagonistic activity and α-glucosidase-inhibitory activity, led to the LXRα-selective antagonist 23f. Specific α-glucosidase inhibitors were also obtained.
- Motoshima, Kazunori,Noguchi-Yachide, Tomomi,Sugita, Kazuyuki,Hashimoto, Yuichi,Ishikawa, Minoru
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experimental part
p. 5001 - 5014
(2009/12/24)
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- Fluoride-free cross coupling using vinyldisiloxanes
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Vinyldisiloxanes equilibrate with the corresponding silanolates under basic conditions and subsequently undergo palladium catalysed cross coupling with aryl/heteroaryl iodides and bromides. The Royal Society of Chemistry 2009.
- Sore, Hannah F.,Boehner, Christine M.,MacDonald, Simon J. F.,Norton, David,Fox, David J.,Spring, David R.
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supporting information; experimental part
p. 1068 - 1071
(2009/05/30)
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- Synthesis of stilbenes promoted by the mixture of zinc and iron powder
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Stilbenes have been synthesised by a one-pot reaction of aldehydes with benzyl bromide. The reaction was promoted by both triphenylphosphine and the mixture of zinc and iron together in sealed tube. The yields ranged from moderate to excellent.
- Zhanga, Zhiying,Xieb, Yuanyuan,Yua, Xiaochun
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experimental part
p. 140 - 142
(2009/10/15)
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- Pd-N-heterocyclic carbene (NHC) organic silica: synthesis and application in carbon-carbon coupling reactions
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The first Pd-N-heterocyclic carbene (NHC) complex in the form of organic silica was prepared using sol-gel method and its application in Heck and Suzuki reactions was demonstrated. These C-C coupling reactions proceeded efficiently under the influence of microwave irradiation, with excellent yield, without any change in catalytic activity for at least five reaction cycles, with negligible Pd concentration in the end product.
- Polshettiwar, Vivek,Varma, Rajender S.
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p. 4637 - 4643
(2008/09/20)
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- Palladium-catalyzed cross-coupling of aryl chlorides with alkenylboronic acids with low E/Z isomerization
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Using a bulky electron-rich monodentate benzoferrocenyl phosphine as supporting ligand, an efficient protocol for stereoselective palladium-catalyzed Suzuki-Miyaura cross-coupling of aryl chlorides with alkenylboronic acids was uncovered. Using this protocol, both trans- and cis-alkenylboronic acids can be coupled with high stereoselectivity giving the corresponding vinylarenes in good to quantitative yields. Electron-poor and -rich aryl chlorides including highly hindered ones are all suitable substrates for the reaction.
- Thimmaiah, Muralidhara,Zhang, Xiang,Fang, Shiyue
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p. 5605 - 5607
(2008/12/22)
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- Piperazine-derived palladium complexes immobilised on a Merrifield resin as a catalyst for the Heck reaction
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A palladium catalyst supported on a Merrifield resin was prepared by a simple procedure and exhibited high activity and stability for the phosphine-free Heck reaction of activated and non-activated aryl or heteroaryl substrates with olefins to afford substituted cinnamic acids, stilbenes and their hetero-aromatic relatives.
- Wu, Xiang-Mei,Pei, Wen
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- Amides as precursors of imidoyl radicals in cyclisation reactions
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Amides have been successfully used as precursors of imidoyl radicals for radical cyclisation. The amides have been converted to imidoyl selanides via reaction with phosgene to yield imidoyl chlorides followed by reaction with potassium phenylselanide. Imidoyl selanides were reacted with tributyltin hydride (Bu3SnH) as the radical mediator with triethylborane or AIBN as initiators to yield imidoyl radicals for cyclisation reactions. Imidoyl radicals have been cyclised onto alkenes to yield 2,3-substituted-indoles and -quinolines and also onto pyrroles and indoles to give bi- and tricyclic heteroarenes.
- Bowman, W. Russell,Fletcher, Anthony J.,Pedersen, Jan M.,Lovell, Peter J.,Elsegood, Mark R.J.,Hernández López, Elena,McKee, Vickie,Potts, Graeme B.S.
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p. 191 - 203
(2007/10/03)
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- Thiourea compositions and uses thereof
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The invention provides N,N′-disubstituted monothiourea or bis-thiourea-Pd(0) complexes that are useful as catalysts for palladium-catalyzed Heck reaction of aryl iodides and bromides with olefins, and as catalysts for palladium catalyzed Suzuki reactions of organoboric compounds and aryl halides.
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Page/Page column 4; 11-12
(2008/06/13)
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- Unexpected Z-stereoselectivity in the Ramberg-Baecklund reaction of diarylsulfones leading to cis-stilbenes: The effect of aryl substituants and application in the synthesis of the integrastatin nucleus
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With certain substituent patterns, benzyl benzyl sulfone systems have been found to give unexpectedly high Z-stereoselectivity (up to E : Z = 1 : 16) in the Meyers variant of the Ramberg-Baecklund reaction. A range of sulfones, bearing various aryl substi
- Foot, Jonathan S.,Giblin, Gerard M.P.,Whitwood,Taylor
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p. 756 - 763
(2007/10/03)
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- Sterically bulky thioureas as air- and moisture-stable ligands for pd-catalyzed heck reactions of aryl halides
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We demonstrate that sterically bulky N,N′-disubstituted cyclic thiourea-Pd(0) complexes are air- and moisture-stable and highly active catalysts for palladium-catalyzed Heck reaction of aryl iodides and bromides with olefins (TONs up to 500 000 for the reaction of Phl and methyl acrylate). Even activated aryl chlorides can undergo complete conversion in Bu 4NBr in the presence of 1 mol % Pd catalyst.
- Yang, Dan,Chen, Ying-Chun,Zhu, Nian-Yong
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p. 1577 - 1580
(2007/10/03)
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- Palladium and phase transfer catalyzed heck cross coupling reaction in water under microwave irradiation
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Palladium-catalyzed vinylation of aryl halides in water without organic cosolvent via microwave irradiation under phase transfer conditions gives the trans-stilbenes and substituted trans-cinnamic acid in good to high yield.
- Wang, Jin-Xian,Liu, Zhanxiang,Hu, Yulai,Wei, Bangguo,Bai, Lin
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p. 1607 - 1614
(2007/10/03)
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- The reaction of peroxynitrite with organic molecules bearing a biologically important functionality. The multiplicity of reaction modes as exemplified by hydroxylation, nitration, nitrosation, dealkylation, oxygenation, and oxidative dimerization and cleavage
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The reactions of peroxynitrite with a variety of organic molecules which include a biologically important functionality have been examined to construct a simple model for the peroxynitrite-induced in vivo transformations as well as a chemical probe for the active species involved therein. Phenols were found to undergo hydroxylation, nitration, oxidative dimerization, and oxidation to cyclohexadienones and quinones. The ring nitration of catechol was confirmed for the first time in the in vitro reaction of peroxynitrite. Dealkylation and N-oxide formation were the major reaction modes observed for N,N-dimethyl-p-toluidine. 1,2-Phenylenediamine gave benzotriazole in high yield. The electron-deficient C-C double bond in 1,4-naphthoquinone underwent epoxidation, while the electron-rich C-C double bond in α-methylstyrene suffered oxidative cleavage to acetophenone. The activated double bond in trans-stilbene underwent oxidative cleavage and epoxidation in parallel to give benzaldehyde and trans-stilbene oxide as the major products. The triple bond in diphenylacetylene was simply oxygenated to form benzil, together with trace amounts of ring nitration products. 1-Phenylethanol, imidazole, 2′-deoxyadenosine, and 2′-deoxyguanosine were all quite slow to react, while uracil and cytosine were almost inert to peroxynitrite. The reaction modes exhibited by peroxynitrite are too widespread and complicated to explain the whole mechanistic pathway in terms of a single active species. All reaction modes observed for the peroxynitrite to date could be classified into five categories according to their types: i) electron transfer type, ii) O-electrophilic type, iii) N-electrophilic type, iv) O-nucleophilic type, and v) radical type. Some of these may compete under certain conditions. The active species involved in each of these types of reactions are as follows: i) NO+, NO2, and OH, ii) ONOOH, iii) ONOOH and NO+, iv) OOH- and ONOO-, and v) NO2 and OH.
- Nonoyama, Nobuaki,Oshima, Hiroshi,Shoda, Chizuru,Suzuki, Hitomi
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p. 2385 - 2395
(2007/10/03)
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- o-Nitroaryldioxolane for protection of pheromones. Study of the photodelivery of carbonylic compounds
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o-Nitrophenyldioxolanes 1 to 12 have been prepared and the rate of their photocleavage determined Steric congestion in the molecule causes a decrease of the reaction rate. The decrease in the rate is especially important in the presence of a nitro group in a second phenyl ring.
- Ceita, Luisa,Maiti, Amiya K.,Mestres, Ramon,Tortajada, Amparo
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p. 1023 - 1055
(2007/10/03)
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- Microwave-promoted palladium catalysed Heck cross coupling reaction in water
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Palladium-catalysed vinylation of aryl halides in water without organic cosolvent via microwave irradiation under phase transfer conditions to give the trans-stilbenes and substituted trans-cinnamic acid in good to high yield.
- Wang,Liu,Hu,Wei,Bai
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p. 484 - 485
(2007/10/03)
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- Nucleophilic substitution in the 10,11-dihydrodibenz[b,f]iodepinium cation
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10,11-Dihydrodibenz[b,f]iodepinium tetrafluoroborate gave only 1-(2-azidophenyl)-2-(2-iodophenylethane with the N3- in aqueous DMSO, while -with NO2- it gave 1-(2-nitrophenyl)-2-(2-iodophenyl)ethane (93%), 9,10-dihydrophenanthrene (5%), and traces of phenanthrene. Both in pure and aqueous DMSO this cation with the Br- ion was converted into phenanthrene (80% and 68% respectively) and 1-(2-bromophenyl)-2-(2-iodophenyl)ethane (10 and 20%), while in water it gave 9,10-dihydrophenanthrene (75%) and phenanthrene (5%). A new route for the synthesis of 1-(2-aminophenyl)-2-phenylethane starting from this tetrafluoroborate has been proposed. 1999 KluwerAcademic/Plenum.
- Tolstaya,Sukhomlinova,Vanchikov,Bumagin
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p. 106 - 111
(2007/10/03)
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- Catalytic Effect of Ferrous Chloride in Chloroarylation of Styrene
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Styrene reacts with arenediazonium chlorides in the presence of FeCl2 as catalyst to give 1-chloro-1-phenyl-2-arylethanes along with minor amounts of 1,4-diaryl-2,3-diphenylbutanes. Ferrous chloride turned out to be a more active catalyst in the chloroarylation of styrene than copper chlorides.
- Obushak
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p. 443 - 445
(2007/10/03)
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