- Palladium/Copper Dual Catalysis for the Cross-Coupling of Aryl(trialkyl)silanes with Aryl Bromides
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Whereas aryl(trialkyl)silanes are considered to be ideal organometallic reagents for cross-coupling reactions owing to their stability, low toxicity, solubility, and easy accessibility, they are generally inert under typical cross-coupling conditions. Disclosed herein is a palladium/copper catalytic system that enables the cross-coupling of trimethyl, triethyl, tert-butyldimethyl, and triisopropyl aryl silanes with aryl bromides. This process is applicable to the sequential C?H and C?Si bond arylation of thiophenes and the synthesis of poly(thiophene–fluorene)s.
- Komiyama, Takeshi,Minami, Yasunori,Furuya, Yuki,Hiyama, Tamejiro
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- Trithiocarbonate Anion as a Sulfur Source for the Synthesis of 2,5-Disubstituted Thiophenes and 2-Substituted Benzo[ b]thiophenes
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The trithiocarbonate anion (CS32-) was generated in situ from CS2 and KOH in dimethyl sulfoxide by a simple method and used as a novel synthetic equivalent of the S2- synthon for the synthesis of 2,5-disubstituted thiophenes from 1,3-butadiynes. Additionally, this system was employed for the metal-free synthesis of 2-substituted benzo[b]thiophenes from 2-haloalkynyl (hetero)arenes. These compounds were obtained from a cheap and readily available sulfur source in moderate to good yields, with good functional group tolerance.
- Paix?o, Douglas B.,Rampon, Daniel S.,Salles, Helena D.,Soares, Eduardo G. O.,Bilheri, Filipe N.,Schneider, Paulo H.
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p. 12922 - 12934
(2020/11/26)
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- One-pot synthesis of unsymmetrical 1,3-butadiyne derivatives and their application in the synthesis of unsymmetrical 2,5-diarylthiophenes
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A one-pot protocol was developed for the synthesis of unsymmetrical 1,3-butadiynes. The procedure is based on two sequential reactions: deprotection of R–C≡C–C≡C– C(Me)2OH derivatives in a retro-Favorskii reaction to furnish a terminal 1,3-butadiyne compound, which reacted with aryl iod-ides in a Sonogashira-type cross-coupling reaction catalyzed by Pd(PPh3)4 and CuI, using TBAOH as activator and toluene as solvent under reflux for 10 min. We also studied in situ thiocycli-zation of 1,3-butadiynes, leading to unsymmetrical 2,5-diaryl-thiophenes. The principal features of this method are operational simplicity, good substrate scope, very fast reaction, and high yields.
- Andrade, Camila B.,Carvalho, Diego B.,Trefzger, Ozildéia S.,Kassab, Najla M.,Guerrero, Palimécio G.,Barbosa, Sandro L.,Shiguemoto, Cristiane Y. K.,Baroni, Adriano C. M.
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p. 696 - 704
(2019/01/04)
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- Transition-Metal-Free Sulfuration/Annulation of Alkenes: Economical Access to Thiophenes Enabled by the Cleavage of Multiple C-H Bonds
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A novel, atom economical, and transition-metal-free strategy for the synthesis of thiophenes from substituted buta-1-enes with potassium sulfide has been presented. The reaction achieves double C-S bond formations via cleavage of multiple C-H bonds and provides an efficient approach to access various functionalized thiophenes. Moreover, the strategy can also be used for the synthesis of thiophenes from 1,4-diaryl-1,3-dienes. Mechanistically, DMSO plays a role of oxidant and S3?- in situ generated from K2S is involved.
- Chen, Liang,Min, Hao,Zeng, Weilan,Zhu, Xiaoming,Liang, Yun,Deng, Guobo,Yang, Yuan
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supporting information
p. 7392 - 7395
(2019/01/03)
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- Arylation method of thiophene compounds
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The invention provides an arylation method of thiophene compounds. The thiophene compounds are benzothiophene or thiophene, and the benzothiophene represented by formula (1) or thiophene represented by formula (2) and aryl chloride represented by formula
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Paragraph 0048; 0049; 0050; 0051; 0052; 0053
(2017/08/28)
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- Sequential one pot double C[sbnd]H heteroarylation of thiophene using bromopyridines to synthesize unsymmetrical 2,5-bipyridylthiophenes
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We present C[sbnd]H heteroarylation reactions between thiophene and variously substituted bromopyridines. The objective was to synthesize unsymmetrical 2,5-bipyridylthiophenes. We studied the reaction conditions allowing to a sequential one-pot double C[sbnd]H heteroarylation, in a view to introduce two different pyridyl moieties at positions 2 and 5 of the thiophene ring using bromopyridines. 11 original unsymmetrical 2,5-bipyridylthiophenes were synthesized and characterized, including 2,5-di(pyridin-2-yl)thiophenes for which the preparation by classical cross-coupling reactions is challenging. Finally, with the additional synthesis of both an unsymmetrical 2,5-biarylthiophene and an original pyrimidin-thiophene-furan scaffold, we shown that our methodology was also an efficient tool to access to new heterocyclic sequences.
- Kieffer, Charline,Babin, Victor,Jouanne, Marie,Slimani, Ikram,Berhault, Yohann,Legay, Rémi,Sopková-de Oliveira Santos, Jana,Rault, Sylvain,Voisin-Chiret, Anne Sophie
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p. 5509 - 5516
(2017/08/22)
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- N-Heterocyclic carbene-Pd(II)-1-methylimidazole complex catalyzed C[sbnd]H bond arylation of (benzo)thiophenes with aryl chlorides
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NHC-Pd(II)-Im complex showed efficient catalytic activity toward the direct C[sbnd]H bond arylation of (benzo)thiophenes with the challenging aryl chlorides. Under the suitable conditions, all reactions proceeded smoothly to give the desired C[sbnd]H bond
- Yin, Shun-Chao,Zhou, Quan,He, Qian-Wei,Li, Shu-Wan,Qian, Peng-Cheng,Shao, Li-Xiong
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p. 427 - 431
(2017/01/13)
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- Direct C-H Arylation of Heteroarenes with Copper Impregnated on Magnetite as a Reusable Catalyst: Evidence for CuO Nanoparticle Catalysis in Solution
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A reusable copper-based catalyst system was employed for the direct arylation of electron-rich heteroarenes. Under mild and operationally simple reaction conditions good yields and selectivities were obtained using diaryliodonium salts as coupling partners. A combination of experimental methods including kinetic studies, filtration tests, and a series of analytical tools (TXRF, ICP-MS, SEM, XPS, TEM, EFTEM) provide evidence for catalytically active soluble nanoparticles formed from an amorphous heterogeneous precursor. Mechanistic studies hint at a redox-neutral process which promotes counterion dissociation from the diaryliodonium salt by a copper(II) oxide species.
- Vásquez-Céspedes, Suhelen,Chepiga, Kathryn M.,M?ller, Nadja,Sch?fer, Andreas H.,Glorius, Frank
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p. 5954 - 5961
(2016/09/09)
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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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- Design, synthesis, biological evaluation and pharmacokinetics of bis(hydroxyphenyl) substituted azoles, thiophenes, benzenes, and aza-benzenes as potent and selective nonsteroidal inhibitors of 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1)
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17β-Estradiol (E2), the most potent female sex hormone, stimulates the growth of mammary tumors and endometriosis via activation of the estrogen receptor α (ERα). 17β-Hydroxysteroid dehydrogenase type 1 (17β-HSD1), which is responsible for the catalytic r
- Bey, Emmanuel,Marchais-Oberwinkler, Sandrine,Werth, Ruth,Negri, Matthias,Al-Soud, Yaseen A.,Kruchten, Patricia,Oster, Alexander,Frotscher, Martin,Birk, Barbara,Hartmann, Rolf W.
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experimental part
p. 6725 - 6739
(2009/11/30)
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- General facile synthesis of 2,5-diarylheteropentalenes
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Palladium-catalyzed cross-coupling reactions of various heteropentalene derivatives were systematically studied. A general three-step synthesis of 2,5-diarylheteropentalenes involving two Suzuki or Negishi couplings and a regiospecific bromination was developed. Nonsymmetrical 2,5-diaryl-furans, thiophenes, pyrroles, 1,3-thiazoles, 1,3-oxazoles, 1,3,4-thiadiazoles, and 1,3,4-oxadiazoles were prepared in 31-67% isolated yield (three steps).
- Vachal, Petr,Toth, Leslie M.
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p. 7157 - 7161
(2007/10/03)
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- Syntheses and properties of donor - Acceptor-type 2,5-diarylthiophene and 2,5-diarylthiazole
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Equation presented. Syntheses of differently substituted 2,5-diarylthiophenes and 2,5-diarylthiazoles are carried out with the palladium-catalyzed C-H substitution reaction using AgF as an activator. Remarkably strong photoluminescence is observed in 2,5-
- Masui, Kentaro,Mori, Atsunori,Okano, Kunihiko,Takamura, Kenji,Kinoshita, Motoi,Ikeda, Tomiki
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p. 2011 - 2014
(2007/10/03)
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- 1,2-Dithiines and precursors, XVI: Synthesis, structure, and reactivity of non-anellated 1,2-dithiines
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Various monocyclic 1,2-dithiines 6a,b,d-t were prepared via (Z,Z)-1,4-difunctionalized butadienes (4-11,19,20). A twisted cyclic structure A is unequivocally proved rather than of the ringopened valence isomer B. The reactivity of these 1,2-dithiines is d
- Schroth, Werner,Dunger, Simona,Billig, Frank,Spitzner, Roland,Herzschuh, Rainer,Vogt, Almut,Jende, Thomas,Israel, Gunter,Barche, Jens,Stroehl, Dieter,Sieler, Joachim
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p. 12677 - 12698
(2007/10/03)
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- New Thiophene Derivatives as Potential Materials for Non Linear Optics
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A method of synthesis of unsymmetrical 2,5-diarylthiophenes is described using β-chloroacroleins, prepared from acetophenones, and their condensation with sodium sulfide and various benzyl bromides.
- Kirsch, Gilbert,Prim, Damien,Leising, Frederic,Mignani, Gerard
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p. 1005 - 1010
(2007/10/02)
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- Thiophenes useful in control of acarids
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Substituted thiophenes of the following formula, some of which are new compounds, are useful in controlling certain pests, particularly mites: STR1 wherein A, Y and Z are various substituents such as phenyl and substituted phenyl.
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