共查询到20条相似文献,搜索用时 31 毫秒
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M. Sc. Congjun Yu Prof. Dr. Frederic W. Patureau 《Angewandte Chemie (International ed. in English)》2018,57(36):11807-11811
A highly selective CuII‐catalyzed cross‐dehydrogenative ortho‐aminomethylation of phenols with aniline derivatives is described. The corresponding C(sp2)?C(sp3) coupling products were obtained in moderate to excellent yields under mild reaction conditions and with a broad substrate scope. A radical mechanism is proposed. 相似文献
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Wei‐Chun Shih Chu‐Chun Teng Dr. Kanniyappan Parthasarathy Prof. Dr. Chien‐Hong Cheng 《化学:亚洲杂志》2012,7(2):306-313
A convenient method for the synthesis of highly substituted isoquinolines and isoquinolinium salts by the nickel‐catalyzed cyclization of ortho‐haloketoximes and ‐ketimines, respectively, with alkynes is described. The reaction of ortho‐haloketoximes and various alkynes in the presence of [Ni(PPh3)2Br2] and zinc powder in a mixture of acetonitrile and tetrahydrofuran at 80 °C for 15 hours gave 1,3,4‐trisubstituted isoquinoline products in moderate to excellent yields and high regioselectivity. The corresponding isoquinoline N‐oxide was found to be the intermediate in the cyclization reaction pathway. In contrast, the reaction of ortho‐haloketimines and alkynes under similar catalytic conditions in tetrahydrofuran at 70 °C for two hours gave 1,2,3,4‐tetrasubstituted isoquinolinium salts in good to excellent yields. 相似文献
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K. Prasanna U. Perera Khalil A. Abboud Dennis W. Smith Mariusz Krawiec 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(3):o107-o110
The molecule of 3,3′,4,4′‐tetrakis(phenylethynyl)biphenyl, C44H26, is approximately planar and is located on a crystallographic inversion center. Bis[3,4‐bis(phenylethynyl)phenyl] ether, C44H26O, has molecules located on twofold symmetry axes, whereas the molecule of 2,2‐bis[3,4‐bis(phenylethynyl)phenyl]propane, C47H32, does not exhibit any molecular symmetry. 相似文献
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Dr. Dmitry Katayev Kai F. Pfister Timo Wendling Prof. Dr. Lukas J. Gooßen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(32):9902-9905
Various (hetero)arenecarboxylic acids were converted to the corresponding Daugulis amides and nitrated selectively in the ortho‐position in the presence of [CuNO3(PPh3)2] and AgNO2 at 50 °C. A microwave‐assisted saponification allows regenerating the carboxylate group within minutes, which may then be removed tracelessly by protodecarboxylation, or substituted by aryl‐ or alkoxy‐groups via decarboxylative cross‐coupling. 相似文献
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New, sterically demanding 1,3‐dialkylbenzimidazolium salts ( 2a–c ) as N‐heterocyclic‐carbene precursors have been synthesized and characterized. The ortho position of aromatic aldehydes was directly and selectively arylated with aryl chlorides in the presence of a catalytic system prepared in situ from Pd(OAc)2, 1,3‐dialkylbenzimidazolium chlorides ( 2a–c ), and Cs2CO3. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:569–574, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20479 相似文献
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Francesco Risitano Giovanni Grassi Francesco Foti 《Journal of heterocyclic chemistry》2001,38(5):1083-1086
Chromones 1 react with diamine 2 to give various products depending on the nature of the position 3 substituent in the heterocycle. 相似文献
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Dr. Andrew J. Eberhart Harry J. Shrives Estela Álvarez Dr. Amandine Carrër Yuntong Zhang David J. Procter 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(20):7428-7434
A sulfoxide‐directed, metal‐free ortho‐propargylation of aromatics and heteroaromatics exploits intermolecular delivery of a propargyl nucleophile to sulfur followed by an intramolecular relay to carbon. The operationally simple cross‐coupling procedure is general, regiospecific with regard to the propargyl nucleophile, and shows complete selectivity for products of ortho‐propargylation over allenylation. The use of secondary propargyl silanes allows metal‐free ortho‐coupling to form carbon–carbon bonds between aromatic and heteroaromatic rings and secondary propargylic centres. The ‘safety‐catch’ nature of the sulfoxide directing group is illustrated in a selective, iterative double cross‐coupling process. The products of propargylation are versatile intermediates and they have been readily converted into substituted benzothiophenes. 相似文献
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Dr. Yuwen Zeng Dr. Guangyu Li Prof. Dr. Jinbo Hu 《Angewandte Chemie (International ed. in English)》2015,54(37):10773-10777
Described is a one‐pot vicinal fluorination‐iodination of arynes at room temperature. The diphenyliodonium salt proved to be a privileged catalyst for this nucleophilic fluorination process using CsF as a fluorine source, and a subsequent facile electrophilic iodination with C4F9I was also found to be crucial to ensure the efficient fluorination. This new synthetic protocol has a broad substrate scope under mild reaction conditions. 相似文献
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Klara Edel Sarah A. Brough Ashley N. Lamm Shih‐Yuan Liu Holger F. Bettinger 《Angewandte Chemie (International ed. in English)》2015,54(27):7819-7822
The BN analogue of ortho‐benzyne, 1,2‐azaborine, is generated by flash vacuum pyrolysis, trapped under cryogenic conditions, and studied by direct spectroscopic techniques. The parent BN aryne spontaneously binds N2 and CO2, thus demonstrating its highly reactive nature. The interaction with N2 is photochemically reversible. The CO2 adduct of 1,2‐azaborine is a cyclic carbamate which undergoes photocleavage, thus resulting in overall CO2 splitting. 相似文献
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Palladium‐Catalyzed Intermolecular Acylation of Aryl Diazoesters with ortho‐Bromobenzaldehydes
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Yinghua Yu Dr. Qianqian Lu Prof. Dr. Gui Chen Prof. Dr. Chunsen Li Prof. Dr. Xueliang Huang 《Angewandte Chemie (International ed. in English)》2018,57(1):319-323
In this work, we describe a palladium‐catalyzed intermolecular O acylation of α‐diazoesters with ortho‐bromobenzaldehydes. The C(sp2)?H bond activation of the aldehyde is enabled by migratory insertion of a palladium carbene intermediate. The diazoesters act as modular three‐atom units to build up key seven‐membered palladacycles, which are transformed into a variety of isocoumarin derivatives upon reductive elimination. Mechanistic experiments and DFT calculations provide insight into the reaction pathway. 相似文献
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《化学:亚洲杂志》2017,12(4):459-464
A method that allows hindered ortho ‐substituted aryl iodides to be efficiently coupled to phenylboronic acid using a gold‐catalyzed C−C bond formation is presented. The use of a molecularly‐defined dinuclear gold chloride catalytic precursor that is stabilized by a new tetradentate (N ,N′ )‐diamino‐(P,P′ )‐diphosphino ferrocene hybrid ligand in a Suzuki‐type reaction is described for the first time. Electron‐rich isopropyl groups on phosphorus were found essential for a superior activity, while the performances of a set of analogous gold dinuclear complexes that were fully characterized by multinuclear NMR spectroscopy and XRD analysis, were investigated. Therefore, arylation of para and ortho ‐substituted iodoarenes bearing electron‐rich, electron‐poor functional groups, and even hindered polycyclic aromatic compounds is described. 相似文献
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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
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Chuanhu Lei Xiaojia Jin Jianrong Zhou 《Angewandte Chemie (International ed. in English)》2015,54(45):13397-13400
Three‐component couplings were achieved from common aryl halides, alkyl halides, and heteroarenes under palladium and norbornene co‐catalysis. The reaction forges hindered aryl–heteroaryl bonds and introduces ortho‐alkyl groups to aryl rings. Various heterocycles such as oxazoles, thiazoles and thiophenes underwent efficient coupling. The heteroarenes were deprotonated in situ by bases without the assistance of palladium catalysts. 相似文献
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Nicky J. Willis Dr. Christopher D. Bray 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(30):9160-9173
ortho‐Quinone methides (o‐QMs) are emerging as highly useful intermediates, the inherent reactivity of which can be used in linchpin reactions for the construction of complex natural products. This review encompasses the major contributions in this field, exemplifying the major strategies and reactivity modes which can be applied. 相似文献