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1.
Borylation of Unactivated Aryl Chlorides under Mild Conditions by Using Diisopropylaminoborane as a Borylating Reagent 下载免费PDF全文
Dr. Hélène D. S. Guerrand Ludovic D. Marciasini Mélissa Jousseaume Dr. Michel Vaultier Dr. Mathieu Pucheault 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(19):5573-5579
The synthesis of arylboronic ester derivatives from aryl chlorides by using aryl(amino)boranes is described. Palladium‐catalyzed coupling between aryl chlorides and diisopropylaminoborane leads to the formation of a C?B bond under mild conditions. A wide range of functional groups are tolerated, making this method particularly useful for the borylation of functionalized aromatics. 相似文献
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Camille Z. Rubel Yilin Cao Tamara El-Hayek Ewing Gabriele Laudadio Gregory L. Beutner Steven R. Wisniewski Xiangyu Wu Phil S. Baran Julien C. Vantourout Keary M. Engle 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(2):e202311557
Over the last fifty years, the use of nickel catalysts for facilitating organic transformations has skyrocketed. Nickel(0) sources act as useful precatalysts because they can enter a catalytic cycle through ligand exchange, without needing to undergo additional elementary steps. However, most Ni(0) precatalysts are synthesized with stoichiometric aluminum–hydride reductants, pyrophoric reagents that are not atom-economical and must be used at cryogenic temperatures. Here, we demonstrate that Ni(II) salts can be reduced on preparative scale using electrolysis to yield a variety of Ni(0) and Ni(II) complexes that are widely used as precatalysts in organic synthesis, including bis(1,5-cyclooctadiene)nickel(0) [Ni(COD)2]. This method overcomes the reproducibility issues of previously reported methods by standardizing the procedure, such that it can be performed anywhere in a robust manner. It can be transitioned to large scale through an electrochemical recirculating flow process and extended to an in situ reduction protocol to generate catalytic amounts of Ni(0) for organic transformations. We anticipate that this work will accelerate adoption of preparative electrochemistry for the synthesis of low-valent organometallic complexes in academia and industry. 相似文献
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Andre Shavnya Kevin D. Hesp Vincent Mascitti Aaron C. Smith 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(46):13775-13779
A palladium‐catalyzed one‐step synthesis of (hetero)aryl alkyl sulfones from (hetero)arylboronic acids, potassium metabisulfite, and unactivated or activated alkylhalides is described. This transformation is of broad scope, occurs under mild conditions, and employs readily available reactants. A stoichiometric experiment has led to the isolation of a catalytically active dimeric palladium sulfinate complex, which was characterized by X‐ray diffraction analysis. 相似文献
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Palladium‐Catalyzed Synthesis of (Hetero)Aryl Alkyl Sulfones from (Hetero)Aryl Boronic Acids,Unactivated Alkyl Halides,and Potassium Metabisulfite 下载免费PDF全文
Andre Shavnya Dr. Kevin D. Hesp Dr. Vincent Mascitti Dr. Aaron C. Smith 《Angewandte Chemie (International ed. in English)》2015,54(46):13571-13575
A palladium‐catalyzed one‐step synthesis of (hetero)aryl alkyl sulfones from (hetero)arylboronic acids, potassium metabisulfite, and unactivated or activated alkylhalides is described. This transformation is of broad scope, occurs under mild conditions, and employs readily available reactants. A stoichiometric experiment has led to the isolation of a catalytically active dimeric palladium sulfinate complex, which was characterized by X‐ray diffraction analysis. 相似文献
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Hangcheng Ni Prof. Dr. Zaozao Qiu Prof. Dr. Zuowei Xie 《Angewandte Chemie (International ed. in English)》2017,56(3):712-716
Photoarylation of iodocarboranes with unactivated arenes/heteroarenes at room temperature has been achieved, for the first time, thus leading to the facile synthesis of a large variety of cage carbon mono(hetero)arylated and di(hetero)arylated o-carboranes. This work represents a clean, efficient, transition-metal-free, and cheap synthesis of functionalized carboranes, which has significant advantages over the known methods. 相似文献
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《中国化学》2017,35(11):1749-1754
Triphenylphosphine and salicylaldimine could be used as a mixed ligand system to obtain a high catalytic activity for palladium catalyzed diarylation of primary anilines with unactivated aryl chlorides by the synergistic effect of ligands. The activity and selectivity of the catalytic system could be improved by modifying the structure of salicylaldimine. In refluxing o ‐xylene, PdCl2(Ph3P)2 with 2,5‐ditrifluoromethyl N ‐phenylsalicylaldimine as a coligand shows high efficiency for the diarylation of various anilines. The catalytic system shows good toleration for the steric hindrance of the substrates. The facile catalytic system works as well on the multiple arylation of 1,1′‐biphenyl‐ 4,4′‐diamine with aryl chlorides to afford N ,N ,N′ ,N′ ‐tetraaryl‐1,1′‐biphenyl‐4,4′‐diamines which are important intermediates of organic light emitting diode (OLED) hole transport materials. 相似文献
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Ryan T. McGuire Connor M. Simon Dr. Arun A. Yadav Dr. Michael J. Ferguson Prof. Dr. Mark Stradiotto 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(23):9037-9041
The development of Ni-catalyzed C−N cross-couplings of sulfonamides with (hetero)aryl chlorides is reported. These transformations, which were previously achievable only with Pd catalysis, are enabled by use of air-stable ( L )NiCl(o-tol) pre-catalysts (L= PhPAd-DalPhos and PAd2-DalPhos ), without photocatalysis. The collective scope of (pseudo)halide electrophiles (X=Cl, Br, I, OTs, and OC(O)NEt2) demonstrated herein is unprecedented for any reported catalyst system for sulfonamide C−N cross-coupling (Pd, Cu, Ni, or other). Preliminary competition experiments and relevant coordination chemistry studies are also presented. 相似文献
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Dr. Serhii Krykun Dr. Muriel Durandetti 《European journal of organic chemistry》2023,26(4):e202201393
A convenient and efficient approach for the construction of aryl trifluoromethyl selenoethers from aryl iodides under mild conditions is reported. Electrochemical activation of stable and inexpensive NiBr2bipy (bipy – bipyridine) complex instead of labile Ni(COD)2 (COD – cyclooctadiene) catalyst. [NMe4][SeCF3] is employed as shelf-stable source of SeCF3 fragment. The reaction tolerates a wide range of substrates, including modification of drug-like molecules. Cyclic voltammetry studies allow insight into the reaction mechanism. 相似文献
11.
M. Ftima C. Guedes da Silva Anna M. Trzeciak Jzef J. Zilkowski Armando J. L. Pombeiro 《Journal of organometallic chemistry》2001,620(1-2):174-181
The electrochemical behaviour of the set of tetracoordinate rhodium(I) complexes [Rh(O∩O)(CO)L] [O∩O=MeC(O)CHC(O)Me (acac), L=CO (1), P(NC4H4)3 (2), PPh(NC4H4)2 (3), PPh2(NC4H4) (4), PPh3 (5), PCy3 (6), P(OPh)3 (7) or PPh2(C6H4OMe-4) (8); O∩O=PhC(O)CHC(O)Me (bac), L=CO (9) or PPh3 (10); O∩O=PhC(O)CHC(O)CF3(bta), L=CO (11) or PPh3 (12)] and of the pentacoordinate [RhH(CO)L3] [L=P(NC4H4)3 (13), PPh3 (14), P(OPh)3 (15) or P(OC6H4Me-4)3 (16)] and [RhHL4] [L=PPh3 (17) or P(OC6H4Me-3)3 (18)] was studied by cyclic voltammetry and controlled potential electrolysis, in aprotic medium, at a Pt electrode. They present a single-electron oxidation wave (I) (irreversible or quasi-reversible) that can be followed, at a higher potential, by a second and irreversible one (II). The values of first oxidation potential for the tetracoordinate complexes fit the additive Lever's electrochemical parameterisation, and the ligand electrochemical Lever EL and Pickett PL parameters were estimated for the N-pyrrolyl phosphines PPhn(NC4H4)3−n (n=0, 1 or 2) and for the organophosphines PCy3 and PPh2(C6H4OMe-4), the former behaving as weaker net electron donors (the electron donor ability decreases with the increase of the number of N-pyrrolyl groups) than the latter phosphines. The pentacoordinate hydride complexes 13–18 fit a distinct relationship which enabled the estimate of the EL ligand parameter for the phosphites P(OC6H4Me-3)3 and P(OC6H4Me-4)3. Electrochemical metal site parameters were obtained for the square planar and the pentacoordinate Rh(I)/Rh(II) couples and, for the former, the redox potential is shown to present a much higher sensitivity to a change of a ligand than the octahedral redox couples investigated so far. Linear relationships were also observed between the oxidation potential and the PL ligand parameter (for the series [Rh(acac)(CO)L]) or the infrared ν(CO) frequency, and a generalisation of the former type of correlation is proposed for series of square-planar 16-electron complexes [M′SL] with a common 14-electron T-shaped binding metal centre {M′S}. Oxidation of 5 by Ag[PF6] leads to the dimerisation of the derived Rh(II) species. 相似文献
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Nurtalya Alandini Dr. Luca Buzzetti Prof. Dr. Gianfranco Favi Tim Schulte Dr. Lisa Candish Dr. Karl D. Collins Prof. Dr. Paolo Melchiorre 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(13):5286-5291
Herein, we report a one-electron strategy for catalytic amide synthesis that enables the direct carbamoylation of (hetero)aryl bromides. This radical cross-coupling approach, which is based on the combination of nickel and photoredox catalysis, proceeds at ambient temperature and uses readily available dihydropyridines as precursors of carbamoyl radicals. The method's mild reaction conditions make it tolerant of sensitive-functional-group-containing substrates and allow the installation of an amide scaffold within biologically relevant heterocycles. In addition, we installed amide functionalities bearing electron-poor and sterically hindered amine moieties, which would be difficult to prepare with classical dehydrative condensation methods. 相似文献
13.
Junting Hong Qianyi Liu Feng Li Guangcan Bai Guoquan Liu Man Li Onkar S. Nayal Xuefeng Fu Fanyang Mo 《中国化学》2019,37(4):420-420
The back cover picture shows an electrochemical strategy for the borylation of aryl iodides via a radical pathway using current as a driving force. This method features mild reaction conditions, good functional groups tolerance, and prompt reaction time. EPR, CV and DPV experiments verified the formation of aryl radicals in this electrochemical borylation reaction, and the current plays an important role in the generation of radical intermediate. More details are discussed in the article by Mo et al. on page 347–351.
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Novel heteroleptic Ni (II) complexes bearing a highly hindered yet flexible IPr* ligand, Ni (IPr*)(PPh3)Br2 ( 1 ) and Ni (IPr*)(PCy3)Br2 ( 2 ) (IPr* = 1,3-bis(2,6-bis (diphenylmethyl)-4-methylphenyl)imidazol-2-ylidene), were easily prepared in 78% and 89% yield, respectively. Both were characterized by elemental analysis and NMR spectroscopy, and 1 was subjected to X-ray crystallography. Compared with 2 and its analogue bearing a less sterically demanding IPr ligand (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene), complex 1 exhibited superior catalytic activity in the magnesium-mediated reductive coupling of benzyl chlorides with aryl chlorides, featuring outstanding tolerance of both coupling partners with steric demand. This study discloses a ligand-facilitated reductive coupling of benzyl chlorides with aryl chlorides, which provides a new and practical synthetic tool for the synthesis of diarylmethanes. 相似文献
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The potential of the redox couple FeIV=O / FeIII–O is of interest for the reactivity of the high-valent nonheme iron oxidants in enzymes and bioinspired small molecule systems but, unfortunately, experimentally it so far is very poorly described. Discussed are three computational methods that are used in combination with available experimental data derived from titrations of FeIV=O species with ferrocene derivatives in dry acetonitrile, and from spectroelectrochemical titrations of FeIII–OH complexes in wet acetonitrile, i.e. describing the FeIV=O / FeIII–OH couple – both data sets are known to have some ambiguities. First, a DFT-based method is used to compute the E° values of 14 FeIV=O / FeIII–O couples with an error margin of around 110 mV. A subset of four species of the original data set is used to evaluate a DLPNO-CCSD(T) based approach, and another subset of complexes, where the spectroelectrochemically determined FeIV=O / FeIII–OH potentials are also known, are used for a Bordwell-Polanyi analysis, which also yield pKa values. It is shown that the three approaches lead to a consistent picture but due to possible ambiguities with the experimental data, it currently is not possible to fully evaluate the accuracy of the used approaches. 相似文献
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The complex (IPr)Ni(allyl)Cl (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazolidene) catalyzes the cross-coupling reactions of heteroaromatic chlorides with aryl Grignard reagents. Catalyst loadings as low as 0.1 mol % have been used to afford the products in excellent yields. This nickel-based catalytic system also promotes the activation of the C(Ar)-O bond of anisoles in the Kumada-Tamao-Corriu reaction under fairly mild conditions. 相似文献
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Nurtalya Alandini Luca Buzzetti Gianfranco Favi Tim Schulte Lisa Candish Karl D. Collins Paolo Melchiorre 《Angewandte Chemie (International ed. in English)》2020,59(13):5248-5253
Herein, we report a one‐electron strategy for catalytic amide synthesis that enables the direct carbamoylation of (hetero)aryl bromides. This radical cross‐coupling approach, which is based on the combination of nickel and photoredox catalysis, proceeds at ambient temperature and uses readily available dihydropyridines as precursors of carbamoyl radicals. The method's mild reaction conditions make it tolerant of sensitive‐functional‐group‐containing substrates and allow the installation of an amide scaffold within biologically relevant heterocycles. In addition, we installed amide functionalities bearing electron‐poor and sterically hindered amine moieties, which would be difficult to prepare with classical dehydrative condensation methods. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(17):4931-4935
para ‐Selective C−H borylation of benzamides and pyridines has been achieved by cooperative iridium/aluminum catalysis. A combination of iridium catalysts commonly employed for arene C−H borylation and bulky aluminum‐based Lewis acid catalysts provides an unprecedented strategy for controlling the regioselectivity of C−H borylation to give variously substituted (hetero)arylboronates, which are versatile synthetic intermediates for complex multi‐substituted aromatic compounds. 相似文献