- Fast Suzuki-Miyaura cross-coupling reaction with hexacationic triarylphosphine Bn-dendriphos as ligand
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The application of hexa[(dimethylamino)-methyl]-functionalized triphenylphosphine (1) and its benzylammonium salt, Bn-Dendriphos (2), in the Suzuki-Miyaura cross-coupling of aryl bromides with arylboronic acids is described. The 3,5-bis[(benzyldimethylammonio)methyl] substitution pattern in 2 leads to a rate enhancement compared to both the non-ionic parent compound 1 and triphenylphospine (PPh3) itself. At the same time, the resulting catalytic species are stable towards palladium black formation, even at a phosphine/palladium ratio of 1. These observations are attributed to the presence of a total of six ammonium groups in the backbone of the phosphine ligand, which presumably leads to an unsaturated phosphine-palladium complex.
- Snelders, Dennis J. M.,Kreiter, Robert,Firet, Judith J.,Van Koten, Gerard,Gebbink, Robertus J. M. Klein
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Read Online
- Immobilized boronic acid for Suzuki-Miyaura coupling: Application to the generation of pharmacologically relevant molecules
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An synthetic strategy for the generation of a variety of biaryl and related derivatives, based on Suzuki-Miyaura coupling using immobilized boronic acid, is described. The importance of the methodology was demonstrated by its further application to biologically interesting compounds such as 4-biaryl-β-lactams, descripted as cholesterol absorption inhibitors and anti-MRSA active agents, neoflavonoids, imidazoles, isoxazolines, among others.
- Martinez-Amezaga,Delpiccolo,Mata
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Read Online
- Effects of co-solvents on reactions run under micellar catalysis conditions
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The impact of varying percentages of an organic solvent added to reactions run in aqueous nanomicelles as the reaction medium has been investigated. Issues such as rates of reaction, percent conversion, and yield, as well as various practical aspects (e.g
- Gabriel, Christopher M.,Lee, Nicholas R.,Bigorne, Florence,Klumphu, Piyatida,Parmentier, Michael,Gallou, Fabrice,Lipshutz, Bruce H.
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Read Online
- Metal-Free Aryl Cross-Coupling Directed by Traceless Linkers
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The metal-free, highly selective synthesis of biaryls poses a major challenge in organic synthesis. The scope and mechanism of a promising new approach to (hetero)biaryls by the photochemical fusion of aryl substituents tethered to a traceless sulfonamide linker (photosplicing) are reported. Interrogating photosplicing with varying reaction conditions and comparison of diverse synthetic probes (40 examples, including a suite of heterocycles) showed that the reaction has a surprisingly broad scope and involves neither metals nor radicals. Quantum chemical calculations revealed that the C?C bond is formed by an intramolecular photochemical process that involves an excited singlet state and traversal of a five-membered transition state, and thus consistent ipso–ipso coupling results. These results demonstrate that photosplicing is a unique aryl cross-coupling method in the excited state that can be applied to synthesize a broad range of biaryls.
- Haensch, Veit G.,Neuwirth, Toni,Steinmetzer, Johannes,Kloss, Florian,Beckert, Rainer,Gr?fe, Stefanie,Kupfer, Stephan,Hertweck, Christian
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supporting information
p. 16068 - 16073
(2019/11/28)
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- Mild-Base-Promoted Arylation of (Hetero)Arenes with Anilines
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Transition metal-free radical arylation of heteroarenes is achieved at room temperature by simply adding aqueous sodium carbonate to a solution of the corresponding heteroarene and arenediazonium salt, which can even be formed in situ. Such an easy, inexpensive and mild methodology has been optimized and applied to the expeditious modification of interesting molecular cores like naphthylimide or bisthienylcyclopentenes.
- Monzón, Diego M.,Santos, Tanausú,Pinacho-Crisóstomo,Martín, Víctor S.,Carrillo, Romen
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supporting information
p. 325 - 333
(2018/01/15)
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- Molecular Design of Donor-Acceptor-Type Organic Photocatalysts for Metal-free Aromatic C?C Bond Formations under Visible Light
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Metal-free and photocatalytic radical-mediated aromatic C?C bond formations offer a promising alternative pathway to the conventional transition metal-catalyzed cross-coupling reactions. However, the formation of aryl radicals from common precursors such as aryl halides is highly challenging due to their extremely high reductive potential. Here, we report a structural design strategy of donor-acceptor-type organic photocatalysts for visible light-driven C?C bond formations through the reductive dehalogenation of aryl halides. The reduction potential of the photocatalysts could be systematically aligned to be ?2.04 V vs. SCE via a simple heteroatom engineering of the donor-acceptor moieties. The high reductive potential of the molecular photocatalyst could reduce various aryl halides into aryl radicals to form the C?C bond with heteroarenes. The designability of the molecular photocatalyst further allowed the synthesis of a high LUMO (lowest unoccupied molecular orbital) polymer photocatalyst by a self-initiated free radical polymerization without compromising its LUMO level. (Figure presented.).
- Wang, Lei,Byun, Jeehye,Li, Run,Huang, Wei,Zhang, Kai A. I.
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p. 4312 - 4318
(2018/10/02)
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- A Structure-Activity Relationship Study of Bitopic N 6-Substituted Adenosine Derivatives as Biased Adenosine A1 Receptor Agonists
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The adenosine A1 receptor (A1AR) is a potential novel therapeutic target for myocardial ischemia-reperfusion injury. However, to date, clinical translation of prototypical A1AR agonists has been hindered due to dose limiting adverse effects. Recently, we demonstrated that the biased bitopic agonist 1, consisting of an adenosine pharmacophore linked to an allosteric moiety, could stimulate cardioprotective A1AR signaling in the absence of unwanted bradycardia. Therefore, this study aimed to investigate the structure-activity relationship of compound 1 biased agonism. A series of novel derivatives of 1 were synthesized and pharmacologically profiled. Modifications were made to the orthosteric adenosine pharmacophore, linker, and allosteric 2-amino-3-benzoylthiophene pharmacophore to probe the structure-activity relationships, particularly in terms of biased signaling, as well as A1AR activity and subtype selectivity. Collectively, our findings demonstrate that the allosteric moiety, particularly the 4-(trifluoromethyl)phenyl substituent of the thiophene scaffold, is important in conferring bitopic ligand bias at the A1AR.
- Aurelio, Luigi,Baltos, Jo-Anne,Ford, Leigh,Nguyen, Anh T. N.,J?rg, Manuela,Devine, Shane M.,Valant, Celine,White, Paul J.,Christopoulos, Arthur,May, Lauren T.,Scammells, Peter J.
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p. 2087 - 2103
(2018/03/21)
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- CoIII-Catalyzed Isonitrile Insertion/Acyl Group Migration Between C?H and N?H bonds of Arylamides
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A general efficient and site-selective cobalt-catalyzed insertion of isonitrile into C?H and N?H bonds of arylamides through C?H bond activation and alcohol assisted intramolecular trans-amidation is demonstrated. This straightforward approach overcomes the limitation by the presence of strongly chelating groups. Isolation of CoIII-isonitrile complex B has been achieved for the first time to understand the reaction mechanism.
- Kalsi, Deepti,Barsu, Nagaraju,Sundararaju, Basker
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supporting information
p. 2360 - 2364
(2018/02/22)
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- Insights into the Catalytic Activity of [Pd(NHC)(cin)Cl] (NHC=IPr, IPrCl, IPrBr) Complexes in the Suzuki–Miyaura Reaction
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The influence of C4,5-halogenation on palladium N-heterocyclic carbene complexes and their activity in the Suzuki–Miyaura reaction were investigated. Two [Pd(NHC)(cin)Cl] complexes bearing IPrCl and IPrBr ligands (IPr=1,3-bis(2,6-diisopropyl-phenyl)imidazol-2-ylidene; cin=cinnamyl) were synthesized. After determining the electronic and steric properties of these ligands, their properties were compared to those of [Pd(IPr) (cin)Cl]. The three palladium complexes were studied by using DFT calculations to delineate their behavior in the activation step leading to the putative 12-electron active catalyst. Experimentally, their catalytic activity in the Suzuki–Miyaura reaction involving a wide range of coupling partners (30 entries) at low catalyst loading was studied.
- Izquierdo, Frédéric,Zinser, Caroline,Minenkov, Yury,Cordes, David B.,Slawin, Alexandra M. Z.,Cavallo, Luigi,Nahra, Fady,Cazin, Catherine S. J.,Nolan, Steven P.
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p. 601 - 611
(2017/12/26)
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- Photo-oxidative Cross-Dehydrogenative Coupling-Type Reaction of Thiophenes with α-Position of Carbonyls Using a Catalytic Amount of Molecular Iodine
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A metal-free photo-oxidative intermolecular C-H/C-H coupling reaction of thiophenes is demonstrated with carbonyls using a catalytic amount of molecular iodine. In this system, molecular oxygen in the air acted as a terminal oxidant to regenerate molecular iodine. A mechanistic study was also performed.
- Sudo, Yusuke,Yamaguchi, Eiji,Itoh, Akichika
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supporting information
p. 1610 - 1613
(2017/04/13)
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- Visible-light photocatalyzed synthesis of 2-aryl N-methylpyrroles, furans and thiophenes utilizing arylsulfonyl chlorides as a coupling partner
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Visible-light (Blue LED lamp: hν=425±15 nm) photocatalyzed cross-coupling reactions of arylsulfonyl chloride with N-methylpyrrole, furan, thiophene and their derivatives have been achieved in moderate to good yields at room temperature. A plausible mechan
- Natarajan, Palani,Bala, Anu,Mehta,Bhasin
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p. 2521 - 2526
(2016/04/26)
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- Radical C-H arylations of (hetero)arenes catalysed by gallic acid
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Gallic acid efficiently catalyses radical arylations in water-acetone at room temperature. This methodology proved to be versatile and scalable. Therefore, it constitutes a greener alternative to arylation. Moreover, considering that gallic acid is an abundant vegetable tannin, this work also unleashes an alternative method for the reutilisation of bio-wastes.
- Perretti, Marcelle D.,Monzón, Diego M.,Crisóstomo, Fernando P.,Martín, Víctor S.,Carrillo, Romen
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supporting information
p. 9036 - 9039
(2016/07/21)
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- An Indefinitely Air-Stable σ-NiII Precatalyst for Quantitative Cross-Coupling of Unreactive Aryl Halides and Mesylates with Aryl Neopentylglycolboronates
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Three classes of Ni precatalysts based on π-NiII, π-Ni0 and σ-NiII complexes have been elaborated and employed in different laboratories for the functionalization and cross-coupling of otherwise inert aryl C-O, C-Cl, and C-F electrophiles. Various Ni precatalysts, ligands, boron sources, and reaction conditions that were developed in various research groups, necessitated the selection of the most suitable conditions for desired cross-coupling partners. Here a universal, bench-stable, easily prepared NiIICl(1-naphthyl)(PCy3)2/PCy3 σ-complex, for efficient and quantitative cross-coupling of aryl chlorides, bromides, iodides, mesylates, and fluorides with aryl neopentylglycolboronates is reported. This precatalyst will most probably help to advance the applications of Ni catalysis in organic, supramolecular, and macromolecular synthesis and will provide an easier access to the selection of reaction conditions for various transformations.
- Malineni, Jagadeesh,Jezorek, Ryan L.,Zhang, Na,Percec, Virgil
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supporting information
p. 2795 - 2807
(2016/08/31)
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- Integration of borylation of aryllithiums and Suzuki-Miyaura coupling using monolithic Pd catalyst
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Integration of the preparation of arylboronic esters via aryllithiums and Suzuki-Miyaura coupling using monolithic Pd catalyst without an intentionally added base was achieved. A continuous operation has been done successfully for over 21 hours.
- Nagaki,Hirose,Moriwaki,Mitamura,Matsukawa,Ishizuka,Yoshida
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p. 4690 - 4694
(2016/07/07)
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- Kinetic Studies on the Palladium(II)-Catalyzed Oxidative Cross-Coupling of Thiophenes with Arylboron Compounds and Their Mechanistic Implications
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Reaction orders for the key components in the palladium(II)-catalyzed oxidative cross-coupling between phenylboronic acid and ethyl thiophen-3-yl acetate were obtained by the method of initial rates. It turned out that the reaction rate not only depended on the concentration of palladium trifluoroacetate (reaction order: 0.97) and phenylboronic acid (reaction order: 1.26), but also on the concentration of the thiophene (reaction order: 0.55) and silver oxide (reaction order: -1.27). NMR spectroscopy titration studies established the existence of 1:1 complexes between the silver salt and both phenylboronic acid and ethyl thiophen-3-yl acetate. A low inverse kinetic isotope effect (kH/kD=0.93) was determined upon employing the 4-deuterated isotopomer of ethyl thiophen-3-yl acetate and monitoring its reaction to the 4-phenyl-substituted product. A Hammett analysis performed with para-substituted 2-phenylthiophenes gave a negative ρ value for oxidative cross-coupling with phenylboronic acid. Based on the kinetic data and additional evidence, a mechanism is suggested that invokes transfer of the phenyl group from phenylboronic acid to a 1:1 complex of palladium trifluoroacetate and thiophene as the rate-determining step. Proposals for the structure of relevant intermediates are made and discussed.
- Schnapperelle, Ingo,Breitenlechner, Stefan,Bach, Thorsten
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supporting information
p. 18407 - 18416
(2015/12/24)
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- Very efficient and broad-in-scope palladium-catalyzed Hiyama cross-coupling. the role of water and copper(I) salts
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A very high-yielding Pd-catalyzed cross-coupling between aryl halides and aryl(trialkoxy)silanes is achieved in the presence of Cu(i) and a measured amount of water. This novel methodology is useful for the generation of a wide range of biaryls, particularly non-para substituted derivatives, which are usually less reported.
- Traficante, Carla I.,Mata, Ernesto G.,Delpiccolo, Carina M. L.
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p. 26796 - 26800
(2015/03/30)
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- The suzuki-miyaura reaction performed using a palladium-n-heterocyclic carbene catalyst and a weak inorganic base
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N-Heterocyclic carbenes (NHCs) have been shown to be useful ligands for the Suzuki-Miyaura cross-coupling at low catalyst loadings. We now report that the commercially available and air-stable [Pd(IPr)(cin)Cl] pre-catalyst permits the formation of various functionalized biaryls from aryl chlorides and boronic acids (37 examples) under very mild conditions using a mixture of ethanol/water as solvent and an inorganic base. [Pd(IPr)(cin)Cl] permits an operationally simple Suzuki-Miyaura reaction under very mild conditions using a mixture of ethanol/water as solvent and an inorganic base.
- Izquierdo, Frédéric,Corpet, Martin,Nolan, Steven P.
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supporting information
p. 1920 - 1924
(2015/03/18)
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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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- Room-temperature arylation of arenes and heteroarenes with diaryliodonium salts by photoredox catalysis
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Aryl radicals produced by irradiation of diaryliodonium salts with visible light under the catalysis of [Ru(bpy)3]2+ undergo coupling with a wide range of arenes and heteroarenes, affording various biaryls through direct C-H arylation at room temperature. Georg Thieme Verlag Stuttgart · New York.
- Liu, Yu-Xia,Xue, Dong,Wang, Jia-Di,Zhao, Cong-Jun,Zou, Qing-Zhu,Wang, Chao,Xiao, Jianliang
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supporting information
p. 507 - 513
(2013/04/10)
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- A Palladium Bipyridyl Complex Grafted onto Nanosized MCM-41 as a Heterogeneous Catalyst for Negishi Coupling
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The Negishi coupling of aryl bromides or acyl chlorides with organozinc chlorides catalyzed by a palladium bipyridyl complex anchored on nanosized mobile crystalline material 41 (MCM-41) were investigated. The reactions proceeded smoothly with a very low catalyst loading in THF at 70°C for electron-deficient aryl bromides, which gave good to high yields of the Negishi coupling products. However, reactions in toluene at 110°C were required if electron-rich aryl bromides were employed. For acyl chlorides, the reactions could be performed in THF at 50°C and the corresponding ketones and ynones were obtained in high yields. After centrifugation, it was possible to easily recover the supported catalyst from the reaction mixture, and this could be reused several times without any retreatment or regeneration with only a slight decrease in activity.
- Wu, Wei-Yi,Lin, Tze-Chiao,Takahashi, Tamotsu,Tsai, Fu-Yu,Mou, Chung-Yuan
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p. 1011 - 1019
(2013/05/09)
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- Room-temperature Suzuki-Miyaura coupling of heteroaryl chlorides and tosylates
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Suzuki-Miyaura coupling of heteroaryls is an important method for the preparation of compound libraries for medicinal chemistry and materials research. Although many catalysts have been developed, none of them have been generally applicable to the coupling reactions of heteroaryl chlorides and tosylates at room temperature. We discovered that a catalyst combination of Pd(OAc)2 and XPhos (2-dicyclohexylphosphanyl-2',4',6'- triisopropylbiphenyl) could efficiently catalyze these couplings. Besides the choice of catalyst, the use of hydroxide bases in an aqueous alcoholic solvent was essential for fast couplings. These conditions promoted fast release of active catalyst (XPhos)Pd0, and accelerated the transmetalation in the catalytic cycle. Most of the major families of heteroaryl chlorides (31 examples) and tosylates (17 examples) reached full conversion within minutes to hours at room temperature. The method could be easily scaled up for gram-scale synthesis. Furthermore, we examined the relative reactivity of coupling partners in whole reactions. Electron-rich heteroaryl chlorides and tosylates reacted more slowly than electron-deficient ones, in the order of indole, pyrrole furan, thiophene > pyridine. Similarly, electron-deficient arylboronic acids were less reactive than electron-neutral and electron-rich ones. The reactivity trends from this study can help to choose appropriate coupling partners for Suzuki reactions.
- Yang, Junfeng,Liu, Sijia,Zheng, Jian-Feng,Zhou, Jianrong
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supporting information
p. 6248 - 6259,12
(2020/09/16)
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- Direct 2-arylation of thiophene using low loading of a phosphine-free palladium catalyst
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The direct coupling of aryl halides with thiophene would be a considerable advantage for sustainable development because of only HBr associated with a base as by-product is formed and the number of steps to prepare these compounds is less than in more cla
- Bensaid, Souhila,Roger, Julien,Beydoun, Kassem,Roy, David,Doucet, Henri
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experimental part
p. 3524 - 3531
(2011/09/16)
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- Ni(COD)2/PCy3 catalyzed cross-coupling of aryl and heteroaryl neopentylglycolboronates with aryl and heteroaryl mesylates and sulfamates in THF at room temperature
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Reaction conditions for the Ni(COD)2/PCy3 catalyzed cross-coupling of aryl neopentylglycolboronates with aryl mesylates were developed. By using optimized reaction conditions, Ni(COD)2/PCy 3 was shown to be a versatile catalyst for the cross-coupling of a diversity of aryl neopentylglycolboronates with aryl and heteroaryl mesylates and sulfamates containing both electron-donating and electron-withdrawing substituents in their para, ortho, and meta positions in THF at room temperature. This Ni-catalyzed cross-coupling of aryl neopentylglycolboronates is also effective for the synthesis of heterobiaryls and biaryls containing electrophilic functionalities sensitive to organolithium and organomagnesium derivatives. In combination with the recently developed Nicatalyzed neopentylglycolborylation, all Ni-catalyzed routes to functional biaryls and heterobiaryls are now easily accessible (Figure presented).
- Leowanawat, Pawaret,Zhang, Na,Resmerita, Ana-Maria,Rosen, Brad M.,Percec, Virgil
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experimental part
p. 9946 - 9955
(2012/01/15)
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- Synthesis and biological evaluation of salicylate-based compounds as a novel class of methionine aminopeptidase inhibitors
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A series of salicylate-based compounds were designed and synthesized based on the simple function group replacement from our previously reported catechol-containing inhibitors of methionine aminopeptidase (MetAP). Some of these salicylate derivatives showed similar potency and metalloform selectivity, and some showed considerable antibacterial activity. These findings are consistent with our previous conclusion that Fe(II) is the likely metal used by MetAP in bacterial cells and provide new lead structures that can be further developed as novel antibacterial agents.
- Wang, Wen-Long,Chai, Sergio C.,Ye, Qi-Zhuang
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scheme or table
p. 7151 - 7154
(2012/01/06)
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- Negishi cross-coupling reaction catalyzed by an aliphatic, phosphine based pincer complex of palladium. biaryl formation via cationic pincer-type Pd IV intermediates
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The aliphatic, phosphine-based pincer complex [(C10H 13-1,3-(CH2P(Cy2)2)Pd(Cl)] (1) is a highly active Negishi catalyst, enable to quantitatively couple various electronically activated, non-activated, deactivated, sterically hindered and functionalized aryl bromides with various diarylzinc reagents within short reaction times and low catalyst loadings. Experimental observations strongly indicate that a molecular mechanism is operative with initial chloride dissociation of 1 and formation of the cationic T-shaped 14e- complex [(C10H13-1,3-(CH2P(C6H 11)2)2)Pd]+ (B), which undergoes oxidative addition of an aryl bromide (Ar′Br) to yield the cationic, penta-coordinated aryl bromide pincer complexes of type [(C10H 13-1,3-(CH2P(Cy2)2)Pd(Br) (aryl′)]+ (C) with the metal center in the oxidation state of +IV and the aryl unit in cis position relative to the aliphatic pincer core. Subsequent transmetalation with Zn(aryl)2 result in the cationic diaryl pincer complexes of type [(C10H13-1,3-(CH 2P(Cy2)2)Pd(aryl)(aryl′)]+ (D), which reductively eliminate the coupling products, thereby regenerating the catalyst. The neutral square planar aryl pincer complex - a possible key intermediate in the catalytic cycle - was found to be reversibly formed in the reaction mixture but is not involved in the catalytic mechanism. Similarly, palladium nanoparticles as the catalytically active form of 1 could have been excluded. The Royal Society of Chemistry 2011.
- Gerber, Roman,Blacque, Olivier,Frech, Christian M.
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experimental part
p. 8996 - 9003
(2011/10/31)
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- Palladium-catalyzed cross-couplings of lithium arylzincates with aromatic halides: Synthesis of analogues of isomeridianin G and evaluation as GSK-3β inhibitors
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Several analogues of isomeridianin G have been synthesized using palladium-catalyzed cross-coupling reactions of lithium triorganozincates as a key step. The latter have been prepared by deprotonative lithiation followed by transmetalation using ZnCl
- Seggio, Anne,Priem, Ghislaine,Chevallier, Floris,Mongin, Florence
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experimental part
p. 3617 - 3632
(2010/03/05)
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- Synthesis of unsymmetrical heterobiaryls using palladium-catalyzed cross-coupling reactions of lithium organozincates
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Several unsymmetrical heterobiaryls have been synthesized through palladium-catalyzed cross-coupling reactions of lithium triorganozincates. The latter have been prepared by deprotonative lithiation followed by transmetalation using non-hygroscopic ZnCl2-TMEDA (0.33 equiv). Georg Thieme Verlag Stuttgart.
- Seggio, Anne,Jutand, Anny,Priem, Ghislaine,Mongin, Florence
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experimental part
p. 2955 - 2960
(2009/06/27)
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- Palladium-catalyzed Stille cross-coupling reaction of aryl chlorides using a pre-milled palladium acetate and XPhos catalyst system
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A highly active catalyst system based upon a biaryl monophosphine ligand, XPhos, for the palladium-catalyzed Stille reaction has been developed. This method allows for the coupling of aryl chlorides with a range of tributylarylstannanes to produce the corresponding biaryl compounds in good to excellent yields (61-98%) in short reaction times (4 h). Palladium(II) acetate [Pd(OAc)2] and XPhos in a 1:1.1 ratio were milled into a fine powder that was used as pre-catalyst for these reactions.
- Naber, John R.,Buchwald, Stephen L.
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supporting information; experimental part
p. 957 - 961
(2009/05/26)
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- Air-stable and highly active dendritic phosphine oxide-stabilized palladium nanoparticles: Preparation, characterization and applications in the carbon-carbon bond formation and hydrogenation reactions
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Dendrimer-stabilized palladium nanoparticles were formed in the reduction of palldium bis-(acetylacetonate) [Pd(acac)2] in the presence of phosphine dendrimer ligands using hydrogen in tetrahydrofuran. The resulting Pd nanoparticles were characterized by TEM, 31P NMR and 31P MAS NMR. The results indicated that the dendritic phosphine ligandswere oxidized to phosphine oxides. These dendrimer-stabilized Pd nanoparticles were demonstrated to be efficient catalysts for Suzuki and Stille coupling reactionsand hydrogenations. The dendritic wedges served as a stabilizer for keeping the nanoparticlesfrom aggregating, and asa vehicle for facilitating the separation and/or the recycling of the Pd catalyst. In the case of the Suzuki coupling reaction, these Pd nanoparticles exhibited high catalytic efficiency (TON up to 65,000) and air stability as compared with the commonly used homogeneous catalyst tetrakis(triphenylphosphine)palladium [Pd-(PPh 3)4]. In addition, the results obtained from the bulky dendritic substrate suggest that the Pd nanoparticles might act asres ervoir of catalytically active species, and that the reaction is actually catalyzed by the soluble Pd(0) and/or Pd(II) species leached from the nanoparticle surface.
- Wu, Lei,Li, Zhi-Wei,Zhang, Feng,He, Yan-Mei,Fan, Qing-Hua
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experimental part
p. 846 - 862
(2009/05/07)
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- Exploration of Ionic Liquids as Soluble Supports for Organic Synthesis. Demonstration with a Suzuki Coupling Reaction
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(Equation Presented) The efficiency of ionic liquid supported synthesis was demonstrated by the Suzuki reaction of ionic liquid supported iodobenzoate compounds with arylboronic acids in aqueous media to give, after cleavage with ammonia/methanol, biaryl products in good yields and high purities, without the need for chromatographic purification.
- Miao, Weishi,Chan, Tak Hang
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p. 5003 - 5005
(2007/10/03)
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- N-aryl thienyl-, furyl-, and pyrrolyl-sulfonamides and derivatives thereof that modulate the activity of endothelin
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Thienyl-, furyl- and pyrrolyl-sulfonamides and methods for modulating or altering the activity of the endothelin family of peptides are provided. In particular, N-(isoxazolyl)thienylsulfonamides, N-(isoxazolyl)furylsulfonamides and N-(isoxazolyl)pyrrolylsulfonamides and methods using these sulfonamides for inhibiting the binding of an endothelin peptide to an endothelin receptor by contacting the receptor with the sulfonamide are provided. Methods for treating endothelin-mediated disorders by administering effective amounts of one or more of these sulfonamides or prodrugs thereof that inhibit or increase the activity of endothelin are also provided.
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Page column 114
(2010/01/30)
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- Piperazine compounds as inhibitors of MMP or TNF
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A compound of formula (I) wherein A is a sulfonyl or a carbonyl; R1is an optionally substituted aryl, an optionally substituted heterocyclic group, an optionally substituted lower alkyl or an optionally substituted lower alkenyl; R2is a hydrogen, an optionally substituted lower alkyl, an optionally substituted aryl or an optionally substituted heterocyclic group; R3is an optionally substituted lower alkyl, an optionally substituted lower alkoxy, an optionally substituted aryloxy, an optionally substitued lower alkenyl, an optionally substituted aryl, an optionally substituted heterocyclic group or an optionally substitued amino; R4is a hydrogen, an optionally substituted lower alkyl, an optionally substituted aryl or an optionally substituted heterocyclic group; R5is a hydrogen, an optionally substituted lower alkyl, an optionally substituted aryl or an optionally substituted heterocyclic group; and R10is a hydroxy or a protected hydroxy, and a pharmaceutically acceptable salt thereof. The compound of the present invention is useful as a medicament for prophylactic and therapeutic treatment of MMP- or TNFα-mediated diseases.
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- Exploiting poly(ethylene glycol) as a matrix for liquid-phase organic synthesis
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Soluble polymer-supported chemistry is a technology that allows the blending of the benefits of polymer-supported synthesis and solution-phase chemistry. Herein, we describe our recent efforts in this area targeted at exploring the scope of poly(ethylene glycol) (PEG) as the matrix. Specifically we describe the use of PEG as a support for triphenyl phosphine and for the Stille reaction.
- Sieber, Frank,Wentworth Jr., Paul,Janda, Kim D.
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p. 1018 - 1032
(2007/10/03)
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- Palladium-catalyzed carbon- carbon bond formation on a solid phase utilizing hypervalent iodonium salts
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Palladium-catalyzed cross-coupling of hypervalent iodonium salts with polymer bound alkene, alkyne, and boronate was achieved under mild conditions.
- Kang, Suk-Ku,Yoon, Seok-Keun,Lim, Kwon-Ho,Son, Hoe-Joo,Baik, Tae-Gon
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p. 3645 - 3655
(2007/10/03)
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- Aryl-aryl cross coupling on a solid support using zinc organic reagents and palladium catalysis
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Aryl zinc bromides undergo palladium catalyzed coupling reactions to aryl bromides which are bound to a polystyrene resin via an ester linkage. Liberation of the biaryl carboxylic ester was achieved by transesterification.
- Marquais, Sophie,Arlt, Michael
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p. 5491 - 5494
(2007/10/03)
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- A convenient synthesis of methyl 4-substituted benzoates via Diels-Alder reaction in the presence of palladium on activated carbon
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The thermal reaction of methyl 2-oxo-2H-pyran-5-carboxylates with substituted styrenes in the presence of 10% palladium on activated carbon afforded directly the corresponding methyl 4-biphenylcarboxylates in good yields. By the similar procedure, methyl 4-heteroaryl- and 4-alkyl-substituted benzoates were obtained from heteroaromatic olefines and alkenes, respectively.
- Matsushita,Sakamoto,Murakami,Matsui
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p. 3307 - 3313
(2007/10/02)
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- Novel Immunosuppressive Butenamides
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2-thiophene 12 was carboxylated using butyllithium and carbon dioxide to give 5-thiophene-2-carboxylic acid 13.Conversion of the acid 13 using diphenyl phosphazidate and triethylamine gave 5-4-(1,
- Axton, Christopher A.,Billingham, Michael E. J.,Bishop, Paul M.,Gallagher, Peter T.,Hicks, Terence A.,et al.
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p. 2203 - 2214
(2007/10/02)
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- PALLADIUM-CATALYZED ARYLATION OF FURAN, THIOPHENE, BENZOFURAN AND BENZOTHIOPHENE
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Treatment of ?-electron sufficient aromatic heterocycles such as furan, thiophene, benzofuran and benzothiophene with aryl bromides in the presence of tetrakis(triphenyphosphine)palladium gave the corresponding 2-aryl aromatic heterocycles.
- Ohta, Akihiro,Akita, Yasuo,Ohkuwa, Teruya,Chiba, Mari,Fukunaga, Ryuichi,et al.
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p. 1951 - 1958
(2007/10/02)
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- ARYLATION OF HETEROCYCLES IN THE REACTION OF HETEROCYCLIC MERCURY DERIVATIVES IN THE PRESENCE OF PALLADIUM COMPLEXES
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A convenient method is proposed for the synthesis of aryl derivatives of heterocyclic compounds by the coupling reaction of heterocyclic mercury derivatives and tin derivatives with aryl and heteryl iodides in the presence of palladium complexes.In the case of organotin compounds, the reaction proceeds without the formation of side-products although mercury derivative are usually more available.
- Bumagin, N. A.,Kalinovskii, I. O.,Beletskaya, I. P.
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p. 1159 - 1162
(2007/10/02)
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