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21.
Chemoselective Chromium(II)‐Catalyzed Cross‐Coupling Reactions of Dichlorinated Heteroaromatics with Functionalized Aryl Grignard Reagents 下载免费PDF全文
Dr. Andreas K. Steib Dr. Olesya M. Kuzmina Sarah Fernandez Dr. Sushant Malhotra Prof. Paul Knochel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(5):1961-1965
Chromium(II) chloride catalyzes the chemoselective cross‐coupling reaction of dichloropyridines with a range of functionalized (hetero)aromatic Grignard reagents at room temperature. Functional groups, such as esters and acetals, are well tolerated in this transformation. Previously challenging substrates, quinolines and isoquinolines, participate in the selective Cr‐catalyzed cross‐coupling in cyclopentyl methyl ether (CPME) as the solvent. The effective purging of Cr salts is demonstrated by using various solid supports. 相似文献
22.
Prof. Ian J. S. Fairlamb 《Angewandte Chemie (International ed. in English)》2015,54(36):10415-10427
This Minireview highlights the redox and non‐innocent behavior of NOx ligands (x=1, 2, or 3) in selected Pd‐mediated processes, for example, alkene and aromatic oxidation processes. A focus is placed on mechanistic understanding and linking recent transformations, such as C? H bond activation/functionalization and Wacker oxidation, with previous work on the functionalization of aromatics and alkenes by PdII salts. 相似文献
23.
Substituted Tetraaza‐ and Hexaazahexacenes and their N,N′‐Dihydro Derivatives: Syntheses,Properties, and Structures 下载免费PDF全文
Jens U. Engelhart Dr. Benjamin D. Lindner Manuel Schaffroth David Schrempp Olena Tverskoy Prof. Uwe H. F. Bunz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8121-8129
The palladium‐catalyzed coupling of a substituted o‐diaminoanthracene and a substituted o‐diaminophenazine to substituted 2,3‐dichloroquinoxalines furnishes 10 differently substituted N,N′‐dihydrotetraaza‐ or ‐hexaazahexacenes with the quinoxaline group of the azaacenes carrying fluorine, chlorine, or nitro groups. The N,N′‐dihydrotetraazahexacenes with hydrogen, chlorine, and fluorine subtituents are oxidized to azaacenes, whereas only the parent N,N′‐dihydrohexaazahexacenes, with hydrogen substituents, are oxidized by MnO2. The resultant azaacenes are characterized by their optical and spectroscopic data. In addition, single‐crystal X‐ray structures have been obtained for the parent tetraazahexacenes and their difluoro‐substituted derivatives. The di‐ and tetrachloro derivatives of the N,N′‐dihydrohexaazahexacene have also been structurally characterized. 相似文献
24.
Inside Back Cover: Multiple and Highly Selective Alkyne–Isonitrile C−C and C−N Couplings at Group 4 Metallocenes (Chem. Eur. J. 27/2016) 下载免费PDF全文
25.
An efficient,mild and selective Ullmann‐type N‐arylation of indoles catalysed by Pd immobilized on amidoxime‐functionalized mesoporous SBA‐15 as heterogeneous and recyclable nanocatalyst 下载免费PDF全文
A wide range of N‐arylated indoles were selectively synthesized through intermolecular C(aryl)? N bond formation from the corresponding aryl iodides and indoles through Ullmann‐type coupling reactions in the presence of a catalytic amount of Pd immobilized on amidoxime‐functionalized mesoporous SBA‐15 (SBA‐15/AO/Pd(0)) under mild reaction conditions. These cross‐coupled products were obtained in excellent yields under mild conditions at extremely low palladium loading (ca 0.3 mol%), and the heterogeneous catalyst can be readily recovered by simple filtration and reused seven times with loss in its activity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
26.
Efficient Synthesis of Diaryl Ketones by Nickel‐Catalyzed Negishi Cross‐Coupling of Amides by Carbon–Nitrogen Bond Cleavage at Room Temperature Accelerated by a Solvent Effect 下载免费PDF全文
Shicheng Shi Prof. Dr. Michal Szostak 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(30):10420-10424
The first Negishi cross‐coupling of amides for the synthesis of versatile diaryl ketones by selective C?N bond activation under exceedingly mild conditions is reported. The cross‐coupling was accomplished with bench‐stable, inexpensive precatalyst [Ni(PPh3)2Cl2] that shows high functional‐group tolerance and enables the synthesis of highly functionalized diaryl ketone motifs. The coupling occurred with excellent chemoselectivity favoring the ketone (cf. biaryl) products. Notably, this process represents the mildest conditions for amide N?C bond activation accomplished to date (room temperature, <10 min). Considering the versatile role of polyfunctional biaryl ketone linchpins in modern organic synthesis, availability, and excellent functional‐group tolerance of organozinc reagents, this strategy provides a new platform for amide N?C bond/organozinc cross‐coupling under mild conditions. 相似文献
27.
Inside Back Cover: A Gold(I)‐Catalyzed Domino Coupling of Alcohols with Allenes Enables the Synthesis of Highly Substituted Indenes (Chem. Eur. J. 41/2016) 下载免费PDF全文
28.
Highly Efficient Dehydrogenative Coupling of Hydrosilanes with Amines or Amides Using Supported Gold Nanoparticles 下载免费PDF全文
Dr. Takato Mitsudome Teppei Urayama Dr. Zen Maeno Dr. Tomoo Mizugaki Prof. Dr. Koichiro Jitsukawa Prof. Dr. Kiyotomi Kaneda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3202-3205
Hydroxyapatite‐supported gold nanoparticles (Au/HAP) can act as a highly active and reusable catalyst for the coupling of hydrosilanes with amines under mild conditions. Various silylamines can be selectively obtained from diverse combinations of equimolar amounts of hydrosilanes with amines including less reactive bulky hydrosilanes. This study also highlights the applicability of Au/HAP to the selective synthesis of silylamides through the coupling of hydrosilanes with amides, demonstrating the first example of an efficient heterogeneous catalyst. Moreover, Au/HAP shows high reusability and applicability for gram‐scale synthesis. 相似文献
29.
Stereoselective Preparation of Polyfunctional Alkenylindium(III) Halides and Their Cross‐Coupling with Unsaturated Halides 下载免费PDF全文
Zhi‐Liang Shen Prof. Dr. Paul Knochel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(19):7061-7065
The direct insertion of indium powder to cycloalkenyl iodides in the presence of LiCl in THF allows the preparation of new highly functionalized cycloalkenylindium(III) derivatives. In addition, we discovered that, in contrast to many metal insertions to alkenyl iodides which proceed with a loss of stereochemistry, the insertion of In/LiCl to stereodefined (Z)‐ and (E)‐styryl iodides in THF proceeded with high retention of stereochemistry. After a palladium‐catalyzed cross‐coupling, various polyfunctionalized (Z)‐ and (E)‐stilbenes were obtained with high stereoselectivity. 相似文献
30.
Single Crystal to Single Crystal (SC‐to‐SC) Transformation from a Nonporous to Porous Metal–Organic Framework and Its Application Potential in Gas Adsorption and Suzuki Coupling Reaction through Postmodification 下载免费PDF全文
Dr. Rupam Sen Debraj Saha Dr. Subratanath Koner Dr. Paula Brandão Dr. Zhi Lin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(15):5962-5971
A new amino‐functionalized strontium–carboxylate‐based metal–organic framework (MOF) has been synthesized that undergoes single crystal to single crystal (SC‐to‐SC) transformation upon desolvation. Both structures have been characterized by single‐crystal X‐ray analysis. The desolvated structure shows an interesting 3D porous structure with pendent ?NH2 groups inside the pore wall, whereas the solvated compound possesses a nonporous structure with DMF molecules on the metal centers. The amino group was postmodified through Schiff base condensation by pyridine‐2‐carboxaldehyde and palladium was anchored on that site. The modified framework has been utilized for the Suzuki cross‐coupling reaction. The compound shows high activity towards the C?C cross‐coupling reaction with good yields and turnover frequencies. Gas adsorption studies showed that the desolvated compound had permanent porosity and was microporous in nature with a BET surface area of 2052 m2 g?1. The material also possesses good CO2 (8 wt %) and H2 (1.87 wt %) adsorption capabilities. 相似文献