- Nickel-catalyzed amination of aryl chlorides
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Aryl chlorides are converted to aniline derivatives using catalytic amounts of Ni(COD)2 (COD = 1,5-cyclooctadiene) and DPPF (DPPF = 1,1'- bis(diphenylphosphino)ferrocene) or 1,10-phenanthroline in the presence of sodium tert-butoxide. This procedure has a broad substrate scope: electron- rich or electron-poor aryl chlorides, as well as chloropyridine derivatives, can be combined with primary and secondary amines to give the desired aryl amine products in moderate to excellent yields. Additionally, a procedure which utilizes the air-stable precatalysts (DPPF)NiCl2 or (1,10- phenanthroline)NiCl2 is also described.
- Wolfe, John P.,Buchwald, Stephen L.
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Read Online
- AIR-STABLE NI(0)-OLEFIN COMPLEXES AND THEIR USE AS CATALYSTS OR PRECATALYSTS
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The present invention relates to air stable, binary Ni(0)-olefin complexes and their use in organic synthesis.
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Page/Page column 19
(2021/02/05)
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- Ni(4?Tbustb)3: A robust 16-electron Ni(0) olefin complex for catalysis
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Sixteen-electron Ni(0) complexes bearing trans-stilbene derivative ligands have been shown to display a high degree of stability toward oxidation in the solid state. A structural analysis of a unique family of tris Ni(0) stilbene complexes revealed a remarkable effect of the steric hindrance of the substituents at the para position of the stilbene unit to temperature, oxidation, and degradation in solution. From these analyses, Ni(4?tBustb)3 arose as a long-term air-, bench-. and temperature-stable Ni(0) complex. Importantly, Ni(4?tBustb)3 presents faster kinetic profiles and a broader scope as a Ni(0) source, thus outperforming the previously described Ni(4?CF3stb)3 in a variety of relevant Ni-catalyzed transformations.
- Nattmann, Lukas,Cornella, Josep
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supporting information
p. 3295 - 3300
(2020/10/12)
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- LIGANDS FOR TRANSITION-METAL-CATALYZED CROSS-COUPLINGS, AND METHODS OF USE THEREOF
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Ligands for transition metals are disclosed herein, which may be used in various transition-metal-catalyzed carbon-heteroatom and carbon-carbon bond-forming reactions. The disclosed methods provide improvements in many features of the transition-metal-catalyzed reactions, including the range of suitable substrates, number of catalyst turnovers, reaction conditions, and efficiency. For example, improvements have been realized in transition-metal-catalyzed cross-coupling reactions.
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Page/Page column 130-131; 135
(2009/07/17)
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- A highly active catalyst for Pd-catalyzed amination reactions: Cross-coupling reactions using aryl mesylates and the highly selective monoarylation of primary amines using aryl chlorides
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A catalyst system based on a new biarylmonophosphine ligand (BrettPhos) that shows excellent reactivity for C-N cross-coupling reactions is reported. This catalyst system enables the use of aryl mesylates as a coupling partner in C-N bond-forming reactions. Additionally, the use of BrettPhos permits the highly selective monoarylation of an array of primary aliphatic amines and anilines at low catalyst loadings and with fast reaction times, including the first monoarylation of methylamine. Lastly, oxidative addition complexes of BrettPhos are included, which provide insight into the origin of reactivity for this system. Copyright
- Fors, Brett P.,Watson, Donald A.,Biscoe, Mark R.,Buchwald, Stephen L.
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supporting information; scheme or table
p. 13552 - 13554
(2009/02/06)
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- Simple, efficient catalyst system for the palladium-catalyzed amination of aryl chlorides, bromides, and triflates
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Palladium complexes supported by (o-biphenyl)P(t-Bu)2 (3) or (o- biphenyl)PCy2 (4) are efficient catalysts for the catalytic amination of a wide variety of aryl halides and triflates. Use of ligand 3 allows for the room-temperature catalytic amination of many aryl chloride, bromide, and triflate substrates, while ligand 4 is effective for the amination of functionalized substrates or reactions of acyclic secondary amines. The catalysts perform well for a large number of different substrate combinations at 80-110 °C, including chloropyridines and functionalized aryl halides and triflates using 0.5-1.0 mol % Pd; some reactions proceed efficiently at low catalyst levels (0.05 mol % Pd). These ligands are effective for almost all substrate combinations that have been previously reported with various other ligands, and they represent the most generally effective catalyst system reported to date. Ligands 3 and 4 are air-stable, crystalline solids that are commercially available. Their effectiveness is believed to be due to a combination of steric and electronic properties that promote oxidative addition, Pd-N bond formation, and reductive elimination.
- Wolfe, John P.,Tomori, Hiroshi,Sadighi, Joseph P.,Yin, Jingjun,Buchwald, Stephen L.
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p. 1158 - 1174
(2007/10/03)
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- The Synthesis of Pyridocarbazoles from Diphenylamine Derivatives: Alternative Routes to and Relay Syntheses of Ellipticines and Olivacines
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Two new synthetic routes to pyridocarbazoles are described.In the first, Goldberg-type coupling of various aryl sulfonamides with aryl bromides in the presence of copper and potassium carbonate gives N,N-diaryl sulfonamides.UV irradiation of these, in ethanol, removes the toluene-p-sulfonyl protecting groups and cyclises the diphenylamine moiety to the corresponding carbazoles.These carbazoles are established intermediates in the synthesis of several ellipticines (5,11-dimethylpyridocarbazoles).In a complementary route, a series of substituted acetanilides are similarly coupled under Goldberg conditions with 2-bromo-5-cyanotoluene to give the corresponding cyanodiphenylamines and diphenylamides.Hydrolysis of the latter gives the diphenylamines which are then oxidatively cyclised to 3-cyano-1-methylcarbazoles.Reduction of the cyanocarbazoles leads to 3-formylcarbazoles which are known intermediates for the synthesis of 5-methylpyridocarbazoles.
- Hall, Robin J.,Marchant, Jeremy,Oliveira-Campos, Ana M. F.,Queiroz, Maria-Joao R. P.,Shannon, Patrick V. R.
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p. 3439 - 3450
(2007/10/02)
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