- Ni(II) Precatalysts Enable Thioetherification of (Hetero)Aryl Halides and Tosylates and Tandem C?S/C?N Couplings
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Ni-catalyzed C?S cross-coupling reactions have received less attention compared with other C-heteroatom couplings. Most reported examples comprise the thioetherification of most reactive aryl iodides with aromatic thiols. The use of C?O electrophiles in this context is almost uncharted. Here, we describe that preformed Ni(II) precatalysts of the type NiCl(allyl)(PMe2Ar’) (Ar’=terphenyl group) efficiently couple a wide range of (hetero)aryl halides, including challenging aryl chlorides, with a variety of aromatic and aliphatic thiols. Aryl and alkenyl tosylates are also well tolerated, demonstrating, for the first time, to be competent electrophilic partners in Ni-catalyzed C?S bond formation. The chemoselective functionalization of the C?I bond in the presence of a C?Cl bond allows for designing site-selective tandem C?S/C?N couplings. The formation of the two C-heteroatom bonds takes place in a single operation and represents a rare example of dual electrophile/nucleophile chemoselective process.
- Martín, M. Trinidad,Marín, Mario,Maya, Celia,Prieto, Auxiliadora,Nicasio, M. Carmen
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supporting information
p. 12320 - 12326
(2021/08/09)
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- Palladium-catalyzed heteroaryl thioethers synthesis overcoming palladium dithiolate resting states inertness: Practical road to sulfones and NH-sulfoximines
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We provide efficient synthetic access to heteroaryl sulfones in two-steps using a simple palladium–1,1′-bis[(diphenyl)phosphanyl]ferrocene catalyst to form in high yields variously functionalized heteroaromatic thioethers. Pyridinyl-containing substrates can be subsequently selectively oxidized into sulfones and NH-sulfoximines by using very mild oxidation conditions with a high functional group tolerance. In the palladium-catalyzed C–S coupling of heteroaromatic thiols, reactivity limitation is attached with electron-deficient thiols. We show that this limitation can be resolved by the successful use of 2-bromoheteroarenes in the C–S coupling. We established herein that this choice of heteroaryl electrophilic reagent in palladium-catalyzed C–S bond formation allows overcoming palladium dithiolate out-of-cycle resting state inertness. This was illustrated in the stoichiometric reactivity study of the palladium dithiolate formed from 4-trifluoromethylbenzen-1-thiol –isolated and characterized by multinuclear NMR and XRD– with both 2-chloropyridine and 2-bromopyridine.
- Guilbaud, Johan,Labonde, Marine,Selmi, Awatef,Kammoun, Majed,Cattey, Hélène,Pirio, Nadine,Roger, Julien,Hierso, Jean-Cyrille
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- Thioetherification of Chloroheteroarenes: A Binuclear Catalyst Promotes Wide Scope and High Functional-Group Tolerance
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A constrained binuclear palladium catalyst system affords selective thioetherification of a wide range of functionalized arenethiols with chloroheteroaromatic partners with the highest turnover numbers (TONs) reported to date and tolerates a large variety of reactive functions. The scope of this system includes the coupling of thiophenols with six- and five-membered 2-chloroheteroarenes (i.e., functionalized pyridine, pyrazine, quinoline, pyrimidine, furane, and thiazole) and 3-bromoheteroarenes (i.e., pyridine and furane). Electron-rich congested thiophenols and fluorinated thiophenols are also suitable partners. The coupling of unprotected amino-2-chloropyridines with thiophenol and the successful employment of synthetically valuable chlorothiophenols are described with the same catalyst system. DFT studies attribute the high performance of this binuclear palladium catalyst to the decreased stability of thiolate-containing resting states. Palladium loading was as low as 0.2 mol %, which is important for industrial application and is a step forward in solving catalyst activation/deactivation problems.
- Platon, Mélanie,Wijaya, Novi,Rampazzi, Vincent,Cui, Luchao,Rousselin, Yoann,Saeys, Mark,Hierso, Jean-Cyrille
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p. 12584 - 12594
(2016/08/25)
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- Catalyst-free and base-free water-promoted SNAr reaction of heteroaryl halides with thiols
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A simple and efficient route for the synthesis of biaryl sulfides have been developed in aqueous medium under base- and catalyst-free conditions. A wide variety of heteroaryl halides and thiols underwent SNAr reaction to provide diaryl sulfides in good to excellent yields. The remarkable key features of the reaction include the use of water as an inexpensive and environmentally benign reaction medium, absence of any additional reagent or catalyst, and easy isolation of the products. Georg Thieme Verlag Stuttgart.
- Sreedhar,Surendra Reddy,Amarnath Reddy
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experimental part
p. 1732 - 1738
(2009/12/26)
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- Syntheses and Some Properties of Sulfoxides, Sulfilimines, Aminosulfonium Salts and Sulfoximines Containing Pyridine Nuclei
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Several 2-pyridyl sulfides (1) (e.g., methyl (1a), ethyl (1b), isopropyl (1c), benzyl (1d), 1-phenylethyl (1e), l-menthyl (1f) 2-pyridyl sulfides); and bis(2-pyridylthio)methane (1g), and methyl 2-(N-oxy-pyridyl) sulfide (1h) were prepared by the usual method.Sulfoxides (2) were prepared by oxidation of the corresponding sulfides with m-chloroperbenzoic acid in good yields.A few sulfoxides were found to work as phase-transfer catalysts for some typical nucleophilic reactions in nonpolar solvents such as benzene, and in two-phase systems such as benzene-water.S-2-Pyridyl-N-(p-toluenesulfonyl) sulfinilimines (3) were prepared upon treatment of sulfides with Chloramine-T.Hydrolysis of N-(p-toluenesulfonyl)-2-pyridyl-o-tolylsulfilimine (3i) with conc. sulfuric acid gave the corresponding free sulfilimine in a moderate yield.S-2-Pyridyl sulfoximines (4) were not obtained by the general method from the sulfoxides and hydrazoic acid.Alkyl-2-pyridyl sulfoximines, however, were obtained by oxidation of the free sulfilimines derived from the corresponding aminosulfonium salts (5) prepared by reaction of the sulfides with mesitylene-sulfonylhydroxylamine (MSH).These free sulfilimines and sulfoximines thus prepared were found to give adducts with a few copper salts.
- Furukawa, Naomichi,Takahashi, Fujio,Tsutomu, Kawai,Kishimoto, Keiko,Ogawa, Satoshi,Oae, Shigeru
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p. 167 - 180
(2007/10/02)
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