共查询到20条相似文献,搜索用时 15 毫秒
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Thomas M. Gøgsig Anders T. Lindhardt Dr. Mouloud Dekhane Dr. Julie Grouleff Troels Skrydstrup Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(24):5950-5955
Easy and direct : Regioselective Mizoroki–Heck‐coupling reactions using heteroaromatic tosylates as electrophiles were achieved, thus providing direct and easy access to highly functionalized α‐heteroarylvinyl amides and ethers.
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Olivier Baslé Dr. Nadine Borduas Pauline Dubois Jean Marc Chapuzet Dr. Tak‐Hang Chan Prof. Jean Lessard Prof. Chao‐Jun Li Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(27):8162-8166
The ionic liquid 1‐butyl‐3‐methylimidazolium tetrafluoroborate [BMIm][BF4] has demonstrated high efficiency when applied as a solvent in the oxidative nitro‐Mannich carbon? carbon bond formation. The copper‐catalyzed cross‐dehydrogenative coupling (CDC) between N‐phenyltetrahydroisoquinoline and nitromethane in [BMIm][BF4] occurred with high yield under the described reaction conditions. Both the ionic liquid and copper catalyst were recycled nine times with almost no lost of activity. The electrochemical behavior of the tertiary amine substrate and β‐nitroamine product was investigated employing [BMIm][BF4] as electrolyte solvent. The potentiostatic electrolysis in ionic liquid afforded the desired product with a high yield. This result and the cyclic voltammetric investigation provide a better understanding of the reaction mechanism, which involves radical and iminium cation intermediates. 相似文献
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A copper‐catalyzed migratory oxidative‐coupling reaction between nitrones and various ethers/amines exhibited high functional‐group tolerance. Even in aqueous media, the reaction proceeded efficiently. For practical use of this catalysis, a unique sequential Huisgen cycloaddition was demonstrated. Mechanistic investigations revealed that the reaction proceeded through oxidative catalytic activation of ethers/amines to afford iminium/oxonium intermediates by concurrent dual one‐electron abstractions by copper(II) and oxyl radicals. 相似文献
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Pottabathula Srinivas Pravin R. Likhar Dr. Hariharasarma Maheswaran Dr. Balasubramanian Sridhar Dr. Krishnan Ravikumar Dr. Mannepalli Lakshmi Kantam Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(7):1578-1581
Structurally well defined and thermally stable PdII complexes, derived from N4‐tetradentate dicarboxyamide/dipyridyl ligands, were evaluated as catalysts for the Heck reactions of deactivated aryl chlorides and olefins (see scheme). The concept of using an anionic carboxyamide as an ancillary ligand for palladium demonstrated here provides a new opportunity for the development of phosphine‐free transition‐metal catalysis.
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Masakazu Nambo Kenichiro Itami Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(19):4735-4735
An unexpected C? H bond dimerization reaction and C? C bond‐cleavage reaction in organo(hydro)fullerenes have been discovered. In their Communication on page 4760 ff. , K. Itami and M. Nambo describe the use of Pd catalysts for a number of interesting reactions of such fullerenes.
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Masakazu Nambo Kenichiro Itami Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(19):4760-4764
Palladium can tailor fullerenes : Palladium catalysts enable a number of C? H bond transformations of organo(hydro)fullerene. In addition to anticipated coupling reactions (C? H bond allylation and arylation), an unexpected new C? H bond dimerization reaction and C? C bond‐cleavage reaction were also uncovered.
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Dr. Gregorio Guisado‐Barrios Joanna Hiller Prof. Eduardo Peris 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(31):10405-10411
Two new palladium complexes with a pyracene‐linked bis‐imidazolylidene (pyrabim) group have been obtained and fully characterized. The related monometallic analogues were obtained from the coordination of an acetanaphthene‐supported N‐heterocyclic carbene (NHC). The catalytic properties of all complexes were studied in the acylation of aryl halides with hydrocinnamaldehyde, and in the Suzuki–Miyaura coupling of aryl halides and aryl boronic acids. The results show that the presence of a second metal in the dimetallic complexes induces some benefits in the catalytic behavior of the complexes. This effect is more pronounced in the Suzuki–Miyaura coupling, for which the dimetallic complexes exhibit significantly higher activity than their monometallic counterparts. 相似文献
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Xue‐Yi Chen Charles Barnes Dr. Jerry R. Dias Prof. T. C. Sandreczki Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(9):2041-2044
Triethylamine hydroiodide crystals were formed during Sonogashira reactions; after complete reaction the solution retains a characteristic light color (see picture). Very sluggish Sonogashira reactions of electron‐enriched aryl diiodides have been carried out in high yield in an oxygen‐free, two‐chamber reaction system. The formation of triethylamine hydroiodide crystals was monitored to determine the completion of reaction.
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Erik P. A. Couzijn Dr. Eva Zocher Dr. Andreas Bach Dr. Peter Chen Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(18):5408-5415
Energy‐resolved collision‐induced dissociation experiments using tandem mass spectrometry are reported for an phenylpalladium N‐heterocyclic carbene (NHC) complex. Reductive elimination of an NHC ligand as a phenylimidazolium ion involves a barrier of 30.9(14) kcal mol?1, whereas competitive ligand dissociation requires 47.1(17) kcal mol?1. The resulting three‐coordinate palladium complex readily undergoes reductive C? C coupling to give the phenylimidazolium π complex, for which the binding energy was determined to be 38.9(10) kcal mol?1. Density functional calculations at the M06‐L//BP86/TZP level of theory are in very good agreement with experiment. In combination with RRKM modeling, these results suggest that the rate‐determining step for the direct reductive elimination process switches from the C? C coupling step to the fragmentation of the resulting σ complex at low activation energy. 相似文献
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