1494-26-4Relevant academic research and scientific papers
A terphenyl phosphine as a highly efficient ligand for palladium-catalysed amination of aryl halides with 1° anilines
Shi, Ji-cheng,Zhang, Lixue,Zhou, Fabin
, p. 238 - 243 (2021/09/07)
A terphenyl phosphine ligand (2,6-bis(2,4,6-triisopropylphenyl)phenyl-dicyclohexylphosphine, TXPhos) and its supported palladium complex [(TXPhos)(allyl)PdCl] have been developed and the catalyst system is highly efficient in amination of aryl halides with 1° anilines, especially effective for densely functionalized substrates including both partners possessing ortho-ester, acetyl, nitrile and nitro groups. With the TXPhos-supported catalyst system, many partner combinations have been unprecedentedly realized and the base scope has been even extended to KOAc, which is even the best choice in the amination of 2-nitrochlorobenzene.
Benzyloxycalix[8]arene supported Pd-NHC cinnamyl complexes for Buchwald-Hartwig C-N cross-couplings
Abi Fayssal, Sandra,Buendia, Julien,Huc, Vincent,Martini, Cyril,Naret, Timothée,Schulz, Emmanuelle
, p. 5223 - 5231 (2021/08/16)
The scalable synthesis of Pd-NHC cinnamyl complexes supported on benzyloxycalix[8]arene is reported. These catalysts are very active for Buchwald-Hartwig cross-coupling reactions, allowing the coupling of aryl chlorides and bromides with a wide variety of alkyl and aryl amines using low catalytic loadings. The supported complexes also successfully afforded attractive unsymmetrical triarylamines, and in one case, promoted the synthesis of an unprecedented Pd-catalyzed C-H activation product. Thanks to the calixarenic support, the target products could be isolated with low levels of residual palladium, and in some cases, even below the restrictive toxic metal standards applied by the pharmaceutical industry. Through an easy to implement procedure, these perfectly characterised catalysts thus combine the best of homogeneous and heterogeneous catalysis: high efficiency (similar to or even better than the corresponding homogeneous complexes) and low Pd leaching levels expected from heterogeneous catalysts.
Cu-Catalyzed Cross-Coupling of Nitroarenes with Aryl Boronic Acids to Construct Diarylamines
Guan, Xinyu,Zhu, Haoran,Driver, Tom G.
, p. 12417 - 12422 (2021/10/12)
The development and study of a simple copper-catalyzed reaction of nitroarenes with aryl boronic acids to form diarylamines that uses phenyl silane as the stoichiometric terminal reductant is described. This cross-coupling reaction requires as little as 2 mol % of CuX and 4 mol % of diphosphine for success and tolerates a broad range of functional groups on either the nitroarene or the aryl boronic acid to afford the amine in good yield. Mechanistic investigations established that the cross-coupling reaction proceeds via a nitrosoarene intermediate and that copper is required to catalyze both the deoxygenation of the nitroarene to afford the nitrosoarene and C-NAr bond formation of the nitrosoarene with the aryl boronic acid.
Light-Promoted C–N Coupling of Aryl Halides with Nitroarenes
Li, Gang,Yang, Liu,Liu, Jian-Jun,Zhang, Wei,Cao, Rui,Wang, Chao,Zhang, Zunting,Xiao, Jianliang,Xue, Dong
supporting information, p. 5230 - 5234 (2021/02/05)
A photochemical C–N coupling of aryl halides with nitroarenes is demonstrated for the first time. Catalyzed by a NiII complex in the absence of any external photosensitizer, readily available nitroarenes undergo coupling with a variety of aryl halides, providing a step-economic extension to the widely used Buchwald–Hartwig C–N coupling reaction. The method tolerates coupling partners with steric-congestion and functional groups sensitive to bases and nucleophiles. Mechanistic studies suggest that the reaction proceeds via the addition of an aryl radical, generated from a NiI/NiIII cycle, to a nitrosoarene intermediate.
Modified graphene supported Ag-Cu NPs with enhanced bimetallic synergistic effect in oxidation and Chan-Lam coupling reactions
Choudhary, Anu,Gupta, Monika,Kaur, Manpreet,Paul, Satya,Sharma, Chandan,Sharma, Nitika
, p. 30048 - 30061 (2020/10/06)
Herein, well dispersed Ag-Cu NPs supported on modified graphene have been synthesized via a facile and rapid approach using sodium borohydride as a reducing agent under ambient conditions. Dicyandiamide is selected as an effective nitrogen source with TiO2 as an inorganic material to form two kinds of supports, labelled as TiO2-NGO and NTiO2-GO. Initially, the surface area analysis of these two support materials was carried out which indicated that N-doping of GO followed by anchoring with TiO2 has produced support material of larger surface area. Using both types of supports, ten nano-metal catalysts based on Ag and Cu were synthesized. Benefiting from the bimetallic synergistic effect and larger specific surface area of TiO2-NGO, Cu?Ag-TiO2-NGO is found to be a highly active and reusable catalyst out of other synthesized catalysts. It exhibits excellent catalytic activity for oxidation of alcohols and hydrocarbons as well as Chan-Lam coupling reactions. The nanocatalyst is intensively characterized by BET, SEM, HR-TEM, ICP-AES, EDX, CHN, FT-IR, TGA, XRD and XPS. This journal is
Nickel Dual Photoredox Catalysis for the Synthesis of Aryl Amines
Key, Ryan J.,Vannucci, Aaron K.
, p. 1468 - 1472 (2018/05/23)
In this work, a new dual photoredox nickel catalysis system has been utilized for the synthesize of aryl amines. Previously, our group has shown that a nickel catalyst in conjunction with a photosensitizer and a sacrificial electron donor can cross-couple C-C bonds via photoredox-assisted reductive coupling. Here we have built upon that system to develop a redox-neutral cross-coupling system for the formation of C-N bonds. The catalytic system is composed of just a nickel cross-coupling catalyst, a Ru photocatalyst, and base and is capable of coupling amines with aryl halides in good to excellent yields. Furthermore, it was found that these reactions are functional under ambient conditions with catalyst loadings of 1 mol %. Spectroscopic studies provide support that this amination mechanism proceeds via a nitrogen-based radical intermediate. This N-radical mechanism offers direct synthetic access to di- and triaryl amines from nickel photocatalysis.
Efficient and versatile buchwald-hartwig amination of (hetero)aryl chlorides using the Pd-PEPPSI-IPr(NMe2)2 precatalyst in the presence of carbonate base
Zhang, Yin,César, Vincent,Lavigne, Guy
, p. 2042 - 2050 (2015/03/18)
The precatalyst Pd-PEPPSI-IPr(NMe2)2, in which the IPr ligand was modified by attachment of two dimethylamino groups on to the 4- and 5-positions of the imidazolyl heterocycle, was found to show high catalytic efficiency in the Buchwald-Hartwig amination under mild conditions using Cs2CO3 as a weak base, using a low catalyst loading of 1 mol-%. The protocol is applicable to aryl chlorides bearing base-sensitive substituents, as exemplified by the coupling of 4-chloroacetophenone with aniline. It can also be used with an unprecedentedly wide range of amines, including strongly basic secondary alkylamines, primary arylamines, and primary alkylamines. The Palladium precatalyst Pd-PEPPSI-IPr(NMe2)2, whose supporting N-heterocyclic carbene ligand was decorated with two dimethylamino groups, was found to catalyse the Buchwald-Hartwig amination of aryl halides with a wide range of amines under mild conditions using cesium carbonate as base.
Skeleton decoration of NHCs by amino groups and its sequential booster effect on the palladium-catalyzed Buchwald-Hartwig amination
Zhang, Yin,Cesar, Vincent,Storch, Golo,Lugan, Noel,Lavigne, Guy
supporting information, p. 6482 - 6486 (2014/06/24)
A challenging synthetic modification of PEPPSI-type palladium pre-catalysts consisting of a stepwise incorporation of one and two amino groups onto the NHC skeleton was seen to exert a sequential enhancement of the electronic donor properties. This appears to be positively correlated with the catalytic performances of the corresponding complexes in the Buchwald-Hartwig amination. This is illustrated, for example, by the quantitative amination of 4-chloroanisole by morpholine within 2 h at 25°C with a 2 mol% catalyst/substrate ratio or by a significant reduction of catalytic loading (down to 0.005 mol%) for the coupling of aryl chlorides with anilines (max TON: 19600).
Room-temperature amination of deactivated aniline and aryl halide partners with carbonate base using a Pd-PEPPSI-IPentCl-o-picoline catalyst
Pompeo, Matthew,Farmer, Jennifer L.,Froese, Robert D. J.,Organ, Michael G.
supporting information, p. 3223 - 3226 (2014/04/03)
Current state-of-the-art protocols for the coupling of unreactive amines (e.g., electron-poor anilines) with deactivated oxidative-addition partners (e.g., electron-rich and/or hindered aryl chlorides) involve strong heating (usually >100 °C) and/or tert-butoxide base, and even then not all couplings are successful. The aggressive base tert-butoxide reacts with and in many instances destroys the typical functional groups that are necessary for the function of most organic molecules, such as carbonyl groups, esters, nitriles, amides, alcohols, and amines. The new catalyst described herein, Pd-PEPPSI-IPentCl-o-picoline, is able to aminate profoundly deactivated coupling partners when using only carbonate base at room temperature. Running mild: An N-heterocyclic carbene complex of palladium (1) was systematically designed to enable the amination of strongly deactivated substrates (R1 can be strongly electron donating, R2 can be strongly electron-withdrawing) when using the most mild of bases (carbonate) at room temperature. This catalyst was used to produce elaborate, richly functionalized products for use in life-, health-, and material-science applications.
