共查询到20条相似文献,搜索用时 15 毫秒
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Pd(II)-catalyzed intramolecular amination of sp2 and sp3 C-H bonds are developed using a combination of CuCl2 and AgOAc as the oxidant. The reaction protocol tolerates the presence of a double bond in the substrates. This catalytic reaction provides practical access to a wide range of beta-, gamma-, and delta-lactams. 相似文献
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Stereoselective palladium-catalyzed synthesis of structurally versatile indoline derivatives, using molecular oxygen as the sole oxidant, is described. New C-N and C-C bonds form across an alkene in an intramolecular manner. The C-N bond-forming step proceeds via a syn-amidopalladation pathway. The moderate kinetic isotope effects (intramolecular KIE = 3.56) suggest that electrophilic aromatic substitution occurs in the arylation step. 相似文献
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Bruce H. Lipshutz Daniel Pollart Joseph Monforte Hiyoshizo Kotsuki 《Tetrahedron letters》1985,26(6):705-708
PdCl2(CH3CN)2 catalyzes the hydrolysis of dioxolane acetals and ketals in moist CH3CN, while in acetoze, efficient and more reproducible exchange reactions take place. 相似文献
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Use of a base-free Pd(DMSO)(2)(TFA)(2) catalyst system enables the synthesis of six-membered nitrogen heterocycles via a Wacker-type aerobic oxidative cyclization of alkenes bearing tethered sulfonamides. Various heterocycles, including morpholines, piperidines, piperazines, and piperazinones, are accessible by this method. 相似文献
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Xiang-Ying Tang 《Tetrahedron》2009,65(43):8863-778
Pd(0) catalyzed reactions of methylenecyclopropyl carbonyl compounds afforded a convenient method for the synthesis of conjugate (E,E)-1,3-diene derivatives 2 in good to excellent yields. Moreover, we also found that Pd(II)-catalyzed reactions of methylenecyclopropyl carbonyl compounds with water gave 1,5-diketones in good to high yields via a carbene-palladium intermediate. The plausible reaction mechanisms have also been provided on the basis of control and 18O-labeling experiments. 相似文献
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Palladium-catalyzed oxygenation of allyl arenes or alkenes has been developed to produce (E)-alkenyl aldehydes with high yields. Allylic C-H bond cleavages occur under the mild conditions during this process. Mechanistic studies show that oxygen source is water. 相似文献
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Streuff J Hövelmann CH Nieger M Muñiz K 《Journal of the American Chemical Society》2005,127(42):14586-14587
Intramolecular diamination reactions are described which yield cyclic ureas as direct products of an oxidative alkene transformation in the presence of palladium acetate and iodosobenzene diacetate as terminal oxidant. The reaction is truly catalytic in metal catalyst and represents the proof of principle for this elusive type of alkene oxidation. 相似文献
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Readily available Pd(II) chloride catalysts can catalyze selective and efficient oxidative coupling between N-aryl-2-aminopyridines and internal alkynes to yield N-(2-pyridyl)indoles. This process involves the ortho C-H activation of N-aryl-2-aminopyridines, and CuCl(2) was used as an oxidant. Compared to our previously reported Rh(III)-catalyzed synthesis of this class of product, this method is advantageous with a wider scope of alkynes and cost-effective Pd(II) catalysts. Molecular oxygen can be used as a terminal oxidant. 相似文献
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Victor Hadi 《Tetrahedron letters》2009,50(20):2370-3090
The enyne, ubiquitous in natural products, can be a challenge to generate since these moieties require many synthetic transformations to assemble them. We developed a simpler protocol to construct enynes while we found that this oxidative reaction was tolerant in substrate scope. In addition, the utility of this reaction was demonstrated through the attempt in synthesizing antifungal agent Lamisil™. 相似文献
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Commercially available pyridine ligands can significantly enhance the rate, yield, substrate scope, and site selectivity of arene C-H olefination (Fujiwara-Moritani) reactions. The use of a 1:1 ratio of Pd/pyridine proved critical to maximize reaction rates and yields. 相似文献
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Wasa M Engle KM Lin DW Yoo EJ Yu JQ 《Journal of the American Chemical Society》2011,133(49):19598-19601
Systematic ligand development has led to the identification of novel mono-N-protected amino acid ligands for Pd(II)-catalyzed enantioselective C-H activation of cyclopropanes. A diverse range of organoboron reagents can be used as coupling partners, and the reaction proceeds under mild conditions. These results provide a new retrosynthetic disconnection for the construction of enantioenriched cis-substituted cyclopropanecarboxylic acids. 相似文献
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Lin S Song CX Cai GX Wang WH Shi ZJ 《Journal of the American Chemical Society》2008,130(39):12901-12903
The first catalytic direct alkylation of allylic C-H bonds via Pd(II)-catalysis is described in the absence of base. Polysubstituted cyclic compounds can also be constructed by the intramolecular direct allylic alkylation. 相似文献
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Miklós Orbán 《Reaction Kinetics and Catalysis Letters》1990,42(2):343-353
The role of copper ions in the copper-catalyzed chemical reactions is discussed. It is pointed out that copper ions can induce oscillatory behavior in many systems for the following reasons: (1) Copper cations can exist in three oxidation states (+1, +2 and +3); (2) Copper cations can form precipitates and stable complexes with a large number of reactants and intermediates; (3) Copper ions can participate in both oxidation and reduction processes, due to the surprisingly large range of redox potentials exhibited by the Cu2+/Cu+ and Cu3+/Cu2+ couples (known redox potentials span from 0.1 to 1.8 V, depending on the counter-ion or ligand present). 相似文献
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Radhey S. Srivastava Roy Bertrand IIIAugust A. Gallo Kenneth M. Nicholas 《Tetrahedron letters》2011,52(27):3478-3480
Allylic hydrocarbons are selectively converted to the corresponding allyl amines in good to excellent yield by reaction with aryl hydroxylamines catalyzed by a 1:1 mixture of CuCl and CuCl2 (10 mol %). Under these conditions unsymmetrical olefins react highly regioselectively with N-functionalization at the less substituted vinylic carbon. Trapping experiments indicate that a free nitrosoarene is not an intermediate in these reactions. 相似文献