共查询到20条相似文献,搜索用时 15 毫秒
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Keisho Okura Tsuyoshi Teranishi Yuto Yoshida Prof. Dr. Eiji Shirakawa 《Angewandte Chemie (International ed. in English)》2018,57(24):7186-7190
Arylboroxines in combination with zinc chloride and potassium tert‐butoxide were found to undergo the electron‐catalyzed cross‐coupling with aryl iodides to give the corresponding biaryls without the aid of transition‐metal catalysis. 相似文献
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Significant Enhancement in the Efficiency and Selectivity of Iron‐Catalyzed Oxidative Cross‐Coupling of Phenols by Fluoroalcohols 下载免费PDF全文
Eden Gaster Yulia Vainer Almog Regev Dr. Sachin Narute Dr. Kavitha Sudheendran Aviya Werbeloff Hadas Shalit Dr. Doron Pappo 《Angewandte Chemie (International ed. in English)》2015,54(14):4198-4202
Significant enhancement of both the rate and the chemoselectivity of iron‐catalyzed oxidative coupling of phenols can be achieved in fluorinated solvents, such as 1,1,1,3,3,3‐hexafluoropropan‐2‐ol (HFIP), 2,2,2‐trifluoroethanol (TFE), and 1‐phenyl‐2,2,2‐trifluoroethanol. The generality of this effect was examined for the cross‐coupling of phenols with arenes and polycyclic aromatic hydrocarbons (PAHs) and of phenol with β‐dicarbonyl compounds. The new conditions were utilized in the synthesis of 2′′′‐dehydroxycalodenin B in only four synthetic steps. 相似文献
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Dr. Lulu Fan Jiaqi Jia Dr. Hong Hou Dr. Quentin Lefebvre Prof. Dr. Magnus Rueping 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(46):16437-16440
A mild approach for the decarboxylative aminomethylation of aryl sulfonates by the combination of photoredox and nickel catalysis through C?O bond cleavage is described for the first time. A wide range of aryl triflates as well as aryl mesylates, tosylates and alkenyl triflates afford the corresponding products in good to excellent yields. 相似文献
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Heterogeneous Rhodium‐Catalyzed Aerobic Oxidative Dehydrogenative Cross‐Coupling: Nonsymmetrical Biaryl Amines 下载免费PDF全文
Dr. Kenji Matsumoto Prof. Masahiro Yoshida Prof. Mitsuru Shindo 《Angewandte Chemie (International ed. in English)》2016,55(17):5272-5276
The first heterogeneously catalyzed oxidative dehydrogenative cross‐coupling of aryl amines is reported herein. 2‐Naphthylamine analogues were reacted with various electron‐rich arenes using a heterogeneous Rh/C catalyst under mild aerobic conditions, thus affording nonsymmetrical biaryl amines in excellent yields with high selectivities. This reaction provides a mild, operationally simple, and efficient approach for the synthesis of biaryls which are important to pharmaceutical and materials chemistry. 相似文献
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Ruthenium‐Catalyzed Cross‐Dehydrogenative ortho‐N‐Carbazolation of Diarylamines: Versatile Access to Unsymmetrical Diamines 下载免费PDF全文
Marie‐Laure Louillat Agostino Biafora Fabien Legros Prof. Dr. Frederic W. Patureau 《Angewandte Chemie (International ed. in English)》2014,53(13):3505-3509
The dehydrogenative C–N cross‐coupling of unprotected, secondary anilines through ortho‐N‐carbazolation has been achieved using a Ru catalytic system with O2 as the terminal oxidant. The reactions proceed in an intermolecular fashion, selectively in the ortho position. Implications for the field of organic synthesis are discussed. 相似文献
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Kinetic Resolution of Tertiary Propargylic Alcohols by Enantioselective Cu−H‐Catalyzed Si−O Coupling
Jan Seliger Xichang Dong Martin Oestreich 《Angewandte Chemie (International ed. in English)》2019,58(7):1970-1974
A broad range of tertiary propargylic alcohols were kinetically resolved by catalyst‐controlled enantioselective silylation. This non‐enzymatic kinetic resolution is catalyzed by a Cu?H species and makes use of the commercially available precatalyst MesCu/(R,R)‐Ph‐BPE and a simple hydrosilane as the resolving reagent. Both alkyl,aryl‐ as well as dialkyl‐substituted propargylic alcohols participate, and especially high selectivity factors are achieved when the alkyne terminus carries a TIPS group, which also enables facile post‐functionalization in this position (s up to 207). 相似文献
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Masumi Itazaki Dr. Kensuke Ueda Hiroshi Nakazawa Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(18):3313-3316
A variety of tertiary silanes , even those with functional substituents, undergo an unprecedented iron‐catalyzed dehydrogenative coupling (see scheme) in a convenient approach to disilanes, including unsymmetrical disilanes and polymers with Si? Si bonds in the backbone. Consideration of the catalytic reaction pathway revealed the intermediacy of a hydrido(disilyl)iron(IV) complex.
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Kinetic Resolution of α‐Hydroxy‐Substituted Oxime Ethers by Enantioselective Cu−H‐Catalyzed Si−O Coupling 下载免费PDF全文
Xichang Dong Yuji Kita Prof. Dr. Martin Oestreich 《Angewandte Chemie (International ed. in English)》2018,57(33):10728-10731
A catalyst‐controlled enantioselective alcohol silylation by Cu?H‐catalyzed dehydrogenative Si?O coupling of hydroxy groups α to an oxime ether and simple hydrosilanes is reported. The selectivity factors reached in this kinetic resolution are generally high (s≈50), and these reactions thereby provide reliable access to highly enantioenriched α‐hydroxy‐substituted oxime ethers. The synthetic usefulness of these compounds is also demonstrated. 相似文献
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Copper‐Catalyzed Direct Sulfoximination of Heteroaromatic N‐Oxides by Dual C−H/N−H Dehydrogenative Cross‐Coupling 下载免费PDF全文
A dual C?H/N?H dehydrogenative coupling of quinoline‐type N‐oxides with sulfoximines that leads to N‐(hetero)arylsulfoximines in high yields has been realized by using a catalytic amount of CuBr in air. The method does not require any additional ligand, base, reactivity modifier or oxidant and provides a practical route towards a series of sulfoximidoyl‐functionalized quinolines and derivatives. 相似文献
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Matteo Chierchia Peilin Xu Gabriel J. Lovinger James P. Morken 《Angewandte Chemie (International ed. in English)》2019,58(40):14245-14249
A hybrid transition‐metal/radical process is described that results in the addition of organozinc reagents and alkyl halides across alkenyl boron reagents in an enantioselective catalytic fashion. The reaction can be accomplished both intermolecularly and intramolecularly, providing useful product yields and high enantioselectivities in both manifolds. 相似文献
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Photoinduced Palladium‐Catalyzed Negishi Cross‐Couplings Enabled by the Visible‐Light Absorption of Palladium–Zinc Complexes 下载免费PDF全文
Irini Abdiaj Dr. Lena Huck José Miguel Mateo Prof. Dr. Antonio de la Hoz Dr. M. Victoria Gomez Prof. Dr. Angel Díaz‐Ortiz Dr. Jesús Alcázar 《Angewandte Chemie (International ed. in English)》2018,57(40):13231-13236
A visible‐light‐induced Negishi cross‐coupling is enabled by the activation of a Pd0–Zn complex. With this photocatalytic method, the scope of deactivated aryl halides that can be employed in the Negishi coupling was significantly expanded. NMR experiments conducted in the presence and absence of light confirmed that the formation of the palladium–zinc complex is key for accelerating the oxidative addition step. 相似文献
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Dr. Anna Hedström Dr. Zakieh Izakian Irma Vreto Dr. Carl‐Johan Wallentin Prof. Dr. Per‐Ola Norrby 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(15):5946-5953
The radical nature of iron‐catalyzed cross‐coupling between Grignard reagents and alkyl halides has been studied by using a combination of competitive kinetic experiments and DFT calculations. In contrast to the corresponding coupling with aryl halides, which commences through a classical two‐electron oxidative addition/reductive elimination sequence, the presented data suggest that alkyl halides react through an atom‐transfer‐initiated radical pathway. Furthermore, a general iodine‐based quenching methodology was developed to enable the determination of highly accurate concentrations of Grignard reagents, a capability that facilitates and increases the information output of kinetic investigations based on these substrates. 相似文献
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Zinc‐Catalyzed Dehydrogenative Cross‐Coupling of Terminal Alkynes with Aldehydes: Access to Ynones 下载免费PDF全文
Shan Tang Li Zeng Yichang Liu Prof. Aiwen Lei 《Angewandte Chemie (International ed. in English)》2015,54(52):15850-15853
Because of the lack of redox ability, zinc has seldom been used as a catalyst in dehydrogenative cross‐coupling reactions. Herein, a novel zinc‐catalyzed dehydrogenative C(sp2)? H/C(sp)? H cross‐coupling of terminal alkynes with aldehydes was developed, and provides a simple way to access ynones from readily available materials under mild reaction conditions. Good reaction selectivity can be achieved with a 1:1 ratio of terminal alkyne and aldehyde. Various terminal alkynes and aldehydes are suitable in this transformation. 相似文献
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《中国化学》2018,36(3):233-240
The I2 catalyzed highly selective oxidative condensation of cyclohexenones and alcohols for the synthesis of aryl alkyl ethers has been described. DMSO is employed as the mild terminal oxidant. This novel methodology offers a metal‐free reaction condition, operational simplicity and broad substrate scope to afford valuable products from inexpensive reagents. Various meta‐substituted aromatic ethers which are hardly synthesized from the reported methods requiring meta‐substituted phenols, are efficiently prepared by the present protocol. 相似文献
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Direct Conversion of Alcohols into Alkenes by Dehydrogenative Coupling with Hydrazine/Hydrazone Catalyzed by Manganese 下载免费PDF全文
Dr. Uttam Kumar Das Dr. Subrata Chakraborty Dr. Yael Diskin‐Posner Prof. David Milstein 《Angewandte Chemie (International ed. in English)》2018,57(41):13444-13448
We have developed unprecedented methods for the direct transformation of primary alcohols to alkenes in the presence of hydrazine, and for the synthesis of mixed alkenes by the reaction of alcohols with hydrazones. The reactions are catalyzed by a manganese pincer complex and proceed in absence of added base or hydrogen acceptors, liberating dihydrogen, dinitrogen, and water as the only byproducts. The proposed mechanism, based on preparation of proposed intermediates and control experiments, suggests that the transformation occurs through metal–ligand cooperative N?H activation of a hydrazone intermediate. 相似文献
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