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1.
Palladium‐Catalyzed Cross‐Coupling of Unactivated Aryl Sulfides with Arylzinc Reagents under Mild Conditions 下载免费PDF全文
Shinya Otsuka Dr. Daishi Fujino Dr. Kei Murakami Prof. Dr. Hideki Yorimitsu Prof. Dr. Atsuhiro Osuka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(41):13146-13149
Cross‐coupling of general aryl alkyl sulfides with arylzinc reagents proceeds smoothly, even at room temperature or below, with a palladium–N‐heterocyclic carbene (NHC) catalyst. When combined with reactions that are unique to organosulfurs, that is, the SNAr sulfanylation or Pummerer reaction, the cross‐coupling offers interesting transformations that are otherwise difficult to achieve. An alkylsulfanyl group is preferentially converted whilst leaving the tosyloxy and chloro intact, which expands the variety of orthogonal cross‐coupling. 相似文献
2.
SBA‐15‐functionalized melamine–pyridine group‐supported palladium(0) as an efficient heterogeneous and recyclable nanocatalyst for N‐arylation of indoles through Ullmann‐type coupling reactions 下载免费PDF全文
SBA‐15‐functionalized melamine–pyridine group‐supported palladium(0) was found to serve as a heterogeneous and recyclable nanocatalyst for N‐arylation of indoles with aryl iodides under a low catalyst loading (0.3 mol% of Pd) through Ullmann‐type C? N coupling reactions. A variety of aryl iodides could be aminated to provide the N‐arylated products in good to excellent yields without the need of an inert atmosphere. Also, this catalyst was found to be an efficient system for the N‐arylation of other nitrogen‐containing heterocycles with aryl iodides. The heterogeneous palladium catalyst could be recovered by simple filtration of the reaction solution and reused for six cycles without significant loss in its activity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
3.
Direct C? H arylation of unactivated benzene with aryl halides was achieved using a readily available copper catalyst. The reaction was carried out at 80 °C, using CuBr as catalyst, proline as ligand and t‐BuOK as base. This radical cross‐coupling reaction between unactivated benzene and aryl iodides proceeds via homolytic aromatic substitution and offers an efficient method for the synthesis of various biaryls in good to excellent yields. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
4.
An Alternative to the Classical α‐Arylation: The Transfer of an Intact 2‐Iodoaryl from ArI(O2CCF3)2 下载免费PDF全文
Dr. Zhiyu Jia Dr. Erik Gálvez Prof. Dr. Rosa María Sebastián Prof. Dr. Roser Pleixats Dr. Ángel Álvarez‐Larena Dr. Eddy Martin Prof. Dr. Adelina Vallribera Dr. Alexandr Shafir 《Angewandte Chemie (International ed. in English)》2014,53(42):11298-11301
The α‐arylation of carbonyl compounds is generally accomplished under basic conditions, both under metal catalysis and via aryl transfer from the diaryl λ3‐iodanes. Here, we describe an alternative metal‐free α‐arylation using ArI(O2CCF3)2 as the source of a 2‐iodoaryl group. The reaction is applicable to activated ketones, such as α‐cyanoketones, and works with substituted aryliodanes. This formal C? H functionalization reaction is thought to proceed through a [3,3] rearrangement of an iodonium enolate. The final α‐(2‐iodoaryl)ketones are versatile synthetic building blocks. 相似文献
5.
Nickel‐Catalyzed Cross‐Coupling Reactions of o‐Carboranyl with Aryl Iodides: Facile Synthesis of 1‐Aryl‐o‐Carboranes and 1,2‐Diaryl‐o‐Carboranes 下载免费PDF全文
Cen Tang Prof. Dr. Zuowei Xie 《Angewandte Chemie (International ed. in English)》2015,54(26):7662-7665
A nickel‐catalyzed arylation at the carbon center of o‐carborane cages has been developed, thus leading to the preparation of a series of 1‐aryl‐o‐carboranes and 1,2‐diaryl‐o‐carboranes in high yields upon isolation. This method represents the first example of transition metal catalyzed C,C′‐diarylation by cross‐coupling reactions of o‐carboranyl with aryl iodides. 相似文献
6.
Salt‐Free Reduction of Nonprecious Transition‐Metal Compounds: Generation of Amorphous Ni Nanoparticles for Catalytic C–C Bond Formation 下载免费PDF全文
Dr. Taiga Yurino Yohei Ueda Dr. Yoshiki Shimizu Dr. Shinji Tanaka Haruka Nishiyama Prof. Dr. Hayato Tsurugi Prof. Dr. Kazuhiko Sato Prof. Dr. Kazushi Mashima 《Angewandte Chemie (International ed. in English)》2015,54(48):14437-14441
A salt‐free procedure for the generation of a wide variety of metal(0) particles, including Fe, Co, Ni, and Cu, was achieved using 2,3,5,6‐tetramethyl‐1,4‐bis(trimethylsilyl)‐1,4‐diaza‐2,5‐cyclohexadiene ( 1 ), which reduced the corresponding metal precursors under mild conditions. Notably, Ni particles formed in situ from the treatment of Ni(acac)2 (acac=acetylacetonate) with 1 in toluene exhibited significant catalytic activity for reductive C? C bond‐forming reactions of aryl halides in the presence of excess amounts of 1 . By examination of high‐magnification transmission electron microscopy images and electron diffraction patterns, we concluded that amorphous Ni nanoparticles (Ni aNPs) were essential for the high catalytic activity. 相似文献
7.
Tandem CH Activation/Arylation Catalyzed by Low‐Valent Iron Complexes with Bisiminopyridine Ligands 下载免费PDF全文
Elise Salanouve Ghania Bouzemame Dr. Sébastien Blanchard Dr. Etienne Derat Dr. Marine Desage‐El Murr Prof. Louis Fensterbank 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(16):4754-4761
Tandem C?H activation/arylation between unactivated arenes and aryl halides catalyzed by iron complexes that bear redox‐active non‐innocent bisiminopyridine ligands is reported. Similar reactions catalyzed by first‐row transition metals have been shown to involve substrate‐based aryl radicals, whereas our catalytic system likely involves ligand‐centered radicals. Preliminary mechanistic investigations based on spectroscopic and reactivity studies, in conjunction with DFT calculations, led us to propose that the reaction could proceed through an inner‐sphere C?H activation pathway, which is rarely observed in the case of iron complexes. This bielectronic noble‐metal‐like behavior could be sustained by the redox‐active non‐innocent bisiminopyridine ligands. 相似文献
8.
Ligand‐Enabled Catalytic CH Arylation of Aliphatic Amines by a Four‐Membered‐Ring Cyclopalladation Pathway 下载免费PDF全文
Dr. Chuan He Prof. Matthew J. Gaunt 《Angewandte Chemie (International ed. in English)》2015,54(52):15840-15844
A palladium‐catalyzed C? H arylation of aliphatic amines with arylboronic esters is described, proceeding through a four‐membered‐ring cyclopalladation pathway. Crucial to the successful outcome of this reaction is the action of an amino‐acid‐derived ligand. A range of hindered secondary amines and arylboronic esters are compatible with this process and the products of the arylation can be advanced to complex polycyclic molecules by sequential C? H activation reactions. 相似文献
9.
Dr. Dhananjayan Vasu Prof. Dr. Hideki Yorimitsu Prof. Dr. Atsuhiro Osuka 《Angewandte Chemie (International ed. in English)》2015,54(24):7162-7166
Two new palladium‐catalyzed reactions of aromatic sulfur compounds enabled the conversion of dibenzothiophenes into triphenylenes in four steps. This transformation of one aromatic framework into another consists of 1) 4‐chlorobutylation of the dibenzothiophene to form the corresponding sulfonium salt, 2) palladium‐catalyzed arylative ring opening of the sulfonium salt with a sodium tetraarylborate, 3) an intramolecular SN2 reaction to form a teraryl sulfonium salt, and 4) palladium‐catalyzed intramolecular C? S/C? H coupling through electrophilic palladation. Symmetrical as well as unsymmetrical triphenylenes of interest were synthesized in a tailor‐made fashion in satisfactory overall yields. 相似文献
10.
Through‐Space 1,4‐Palladium Migration and 1,2‐Aryl Shift: Direct Access to Dibenzo[a,c]carbazoles through a Triple CH Functionalization Cascade 下载免费PDF全文
Samir Kumar Bhunia Arghya Polley Dr. Ramalingam Natarajan Dr. Ranjan Jana 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(47):16786-16791
A palladium‐catalyzed expeditious synthesis of dibenzofused carbazoles from readily available 2‐arylindoles and diaryliodonium salts is reported. Interestingly, after the electrophilic C3 palladation of indole, an unexpected “through‐space” 1,4‐palladium migration to the 2‐aryl moiety, by remote C?H bond activation followed by C?H arylation with diaryliodonium salt, and an unprecedented 1,2‐aryl shift take place. Finally, an intramolecular cross‐dehydrogenative coupling (CDC) at the C2 position affords dibenzo[a,c]carbazoles in high yields. Remarkably, the present migratory annulation occurs through three C?H bond activation one C?C bond cleavage, and the simultaneous construction of three new C?C bonds in a single operation. 相似文献
11.
Diaryl Sulfoxides from Aryl Benzyl Sulfoxides: A Single Palladium‐Catalyzed Triple Relay Process 下载免费PDF全文
Tiezheng Jia Dr. Ana Bellomo Dr. Sonia Montel Mengnan Zhang Kawtar EL Baina Bing Zheng Prof. Patrick J. Walsh 《Angewandte Chemie (International ed. in English)》2014,53(1):260-264
A novel approach to produce diaryl sulfoxides from aryl benzyl sulfoxides is reported. Optimization of the reaction conditions was performed using high‐throughput experimentation techniques. The [Pd(dba)2]/NiXantPhos catalyst system successfully promotes a triple relay process involving sulfoxide α‐arylation, C? S bond cleavage, and C? S bond formation. The byproduct benzophenone is formed by an additional palladium‐catalyzed process. It is noteworthy that palladium‐catalyzed benzylative C? S bond cleavage of sulfoxides is unprecedented. A wide range of aryl benzyl sulfoxides, as well as alkyl benzyl sulfoxides with various (hetero)aryl bromides were employed in the triple relay process in good to excellent yields (85–99 %). Moreover, aryl methyl sulfoxides, dibenzyl sulfoxides, and dimethylsulfoxide could be utilized to generate diaryl sulfoxides involving multiple catalytic cycles by a single catalyst. 相似文献
12.
Dehydrogenative Carbon–Carbon Bond Formation Using Alkynyloxy Moieties as Hydrogen‐Accepting Directing Groups 下载免费PDF全文
Dr. Yasunori Minami Tatsuro Kodama Prof. Dr. Tamejiro Hiyama 《Angewandte Chemie (International ed. in English)》2015,54(40):11813-11816
In the presence of a catalyst system consisting of Pd(OAc)2, PCy3, and Zn(OAc)2, the reaction of alkynyl aryl ethers with bicycloalkenes, α,ß‐unsaturated esters, or heteroarenes results in the site‐selective cleavage of two C? H bonds followed by the formation of C? C bonds. In all cases, the alkynyloxy group acts as a directing group for the activation of an ortho C? H bond and as a hydrogen acceptor, thus rendering the use of additives such as an oxidant or base unnecessary. 相似文献
13.
Transition‐Metal‐Free α‐Arylation of Enolizable Aryl Ketones and Mechanistic Evidence for a Radical Process 下载免费PDF全文
Martin Pichette Drapeau Indira Fabre Dr. Laurence Grimaud Dr. Ilaria Ciofini Prof. Dr. Thierry Ollevier Dr. Marc Taillefer 《Angewandte Chemie (International ed. in English)》2015,54(36):10587-10591
The α‐arylation of enolizable aryl ketones can be carried out with aryl halides under transition‐metal‐free conditions using KOtBu in DMF. The α‐aryl ketones thus obtained can be used for step‐ and cost‐economic syntheses of fused heterocycles and Tamoxifen. Mechanistic studies demonstrate the synergetic role of base and solvent for the initiation of the radical process. 相似文献
14.
Readily Removable Directing Group Assisted Chemo‐ and Regioselective C(sp3)H Activation by Palladium Catalysis 下载免费PDF全文
Yun‐Fei Zhang Prof. Dr. Hong‐Wei Zhao Hui Wang Jiang‐Bo Wei Prof. Dr. Zhang‐Jie Shi 《Angewandte Chemie (International ed. in English)》2015,54(46):13686-13690
Currently used directing groups for selective aliphatic β‐functionalization of carbonyl compounds show excellent reactivity and selectivity with an amide as a linker. Described herein is 2‐piconimide, used for the first time with commercially available 2‐picolinamide/2‐picolic acid as precursors, to direct C? H arylation/alkenylation by palladium catalysis. The directing group is essential for promoting the sequnetial primary and secondary C(sp3)? H arylation with different aryl iodides in one substrate. The directing group was easily removed under simple reaction conditions at room temperature. 相似文献
15.
Modular Synthesis of Triarylmethanes through Palladium‐Catalyzed Sequential Arylation of Methyl Phenyl Sulfone 下载免费PDF全文
Dr. Masakazu Nambo Dr. Cathleen M. Crudden 《Angewandte Chemie (International ed. in English)》2014,53(3):742-746
Triarylmethanes, which are valuable structures in materials, sensing and pharmaceuticals, have been synthesized starting from methyl phenyl sulfone as an inexpensive and readily available template. The three aryl groups were installed through two sequential palladium‐catalyzed C? H arylation reactions, followed by an arylative desulfonation. This method provides a new synthetic approach to multisubstituted triarylmethanes using readily available haloarenes and aryl boronic acids, and is also valuable for the preparation of unexplored triarylmethane‐based materials and pharmaceuticals. 相似文献
16.
PdII‐Catalyzed Mild CH ortho Arylation and Intramolecular Amination Oriented by a Phosphinamide Group 下载免费PDF全文
Jing Guan Guo‐Jie Wu Dr. Fu‐She Han 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(12):3301-3305
A novel protocol for the Pd‐catalyzed ortho‐arylation of aryl phosphinamide with boronic acid is reported. By using phosphinamide as a new directing group, the reaction proceeds efficiently under mild conditions at 40 °C. Mechanistic studies reveal that the reaction proceeds via a PdII to Pd0 cycle. The phosphinamide group is also shown to be an effective orienting group for direct C?H amination. 相似文献
17.
Regioselective Ruthenium‐Catalyzed Carbonylative Direct Arylation of Five‐Membered and Condensed Heterocycles 下载免费PDF全文
Jola Pospech Dr. Anis Tlili Dr. Anke Spannenberg Dr. Helfried Neumann Prof. Dr. Matthias Beller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(11):3135-3141
A ruthenium‐catalyzed carbonylative C?H bond arylation process for the three‐component synthesis of complex aryl–(hetero)aryl ketones in an aqueous solution has been developed. By exploiting the ortho‐activating effect of nitrogen‐containing directing groups, a regioselective, successive twofold C(sp2)?C(sp2) bond formation has been achieved. This straightforward catalytic process provides access to versatile products prevalent in multiple bioactive compounds and supplies a valuable functional group for subsequent transformations. 相似文献
18.
Dr. Liangbin Huang Dagmar Hackenberger Prof. Dr. Lukas J. Gooßen 《Angewandte Chemie (International ed. in English)》2015,54(43):12607-12611
In the presence of catalytic [{IrCp*Cl2}2] and Ag2CO3, Li2CO3 as the base, and acetone as the solvent, benzoic acids react with arenediazonium salts to give the corresponding diaryl‐2‐carboxylates under mild conditions. This C? H arylation process is generally applicable to diversely substituted substrates, ranging from extremely electron‐rich to electron‐poor derivatives. The carboxylate directing group is widely available and can be removed tracelessly or employed for further derivatization. Orthogonality to halide‐based cross‐couplings is achieved by the use of diazonium salts, which can be coupled even in the presence of iodo substituents. 相似文献
19.
Single‐Electron‐Transfer‐Induced Coupling of Arylzinc Reagents with Aryl and Alkenyl Halides 下载免费PDF全文
Prof. Eiji Shirakawa Fumiko Tamakuni Eugene Kusano Nanase Uchiyama Wataru Konagaya Ryo Watabe Prof. Tamio Hayashi 《Angewandte Chemie (International ed. in English)》2014,53(2):521-525
Arylzinc reagents, prepared from aryl halides/zinc powder or aryl Grignard reagents/zinc chloride, were found to undergo coupling with aryl and alkenyl halides without the aid of transition‐metal catalysis to give biaryls and styrene derivatives, respectively. In this context, we have already reported the corresponding reaction using aryl Grignard reagents instead of arylzinc reagents. Compared with the Grignard cross‐coupling, the present reaction features high functional‐group tolerance, whereby electrophilic groups such as alkoxycarbonyl and cyano groups are compatible as substituents on both the arylzinc reagents and the aryl halides. Aryl halides receive a single electron and thereby become activated as the corresponding anion radicals, which react with arylzinc reagents, thus leading to the cross‐coupling products. 相似文献
20.
Microwave‐Assisted,Rhodium(III)‐Catalyzed N‐Annulation Reactions of Aryl and α,β‐Unsaturated Ketones with Alkynes 下载免费PDF全文
Hyejeong Lee Yong‐Kyun Sim Dr. Jung‐Woo Park Prof. Dr. Chul‐Ho Jun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(1):323-333
New RhIII‐catalyzed, one‐pot N‐annulation reactions of aryl and α,β‐unsaturated ketones with alkynes in the presence of ammonium acetate have been developed. Under microwave irradiation conditions, the processes lead to rapid formation of the respective isoquinoline and pyridine derivatives with efficiencies that are strongly dependent on the steric nature of the aryl ring and enone substituents. By employing this protocol, a variety of isoquinoline and pyridine derivatives were prepared in high yields. In addition, a new one‐pot approach to the synthesis of pyridines, involving four‐component reactions of ketones, formaldehyde, NH4OAc, and alkynes, has been uncovered. This process takes place through a route involving initial aldol condensation of the ketone with formaldehyde to generate a branched α,β‐unsaturated ketone that then undergoes RhIII‐catalyzed N‐annulation with NH4OAc and the alkyne. 相似文献