نتایج جستجو برای: Palladacycle
تعداد نتایج: 98 فیلتر نتایج به سال:
To facilitate precatalyst recovery and reuse, we have developed a fluorous, oxime-based palladacycle 1 and demonstrated that it is a very efficient and versatile precatalyst for a wide range of carbon-carbon bond formation reactions (Suzuki-Miyaura, Sonogashira, Stille, Heck, Glaser-type, and Kumada) in either aqueous or organic medium under microwave irradiation. Palladacycle 1 could be recove...
Playing it safe: The nontoxic cyanide source K4 [Fe(CN)6]·3H2O can be used for the cyanation of (hetero)aryl halides. The application of palladacycle catalysts prevents poisoning during catalyst formation, thereby allowing for low catalyst loadings, fast reaction times, and wide heterocyclic substrate scope.
A highly efficient and practical protocol for palladacycle-catalyzed decarboxylative coupling of alkynyl carboxylic acids with aryl chlorides was developed. The reaction could proceed smoothly in air within 3 h under optimized reaction conditions (1 mol % of palladacycle, 4 mol % of Xphos, 2.0 equiv of K2CO3 in xylene/H2O), affording the corresponding internal alkynes in mostly good to excellen...
Aryl bromides and iodides in the presence of catalytic amounts of a palladacycle derived from acetophenone oxime and 2 equivalents of potassium acetate react with ethylene under ambient pressure (15-30 psi) to give the corresponding vinylarenes. The reactions work with both electron-deficient and electron-rich aryl compounds and tolerate wide variety of common functional groups. Vinyl bromides ...
Cationic palladium(II) complexes have been found to be highly reactive towards aromatic C-H activation of arylureas at room temperature. A commercially available catalyst [Pd(MeCN)4](BF4)2 or a nitrile-free cationic palladium(II) complex generated in situ from the reaction of Pd(OAc)2 and HBF4, effectively catalyzes C-H activation/cross-coupling reactions between aryl iodides, arylboronic acids...
Tada! Highly functionalized chiral dibenzazepinones are obtained by a mild palladium(0)-catalyzed enantioselective C-H arylation with excellent selectivities by using simple taddol phosphoramidite ligands. The amide tether allows exclusive regioselectivity through a rare eight-membered palladacycle intermediate.
A palladacycle-catalyzed tandem Heck-intramolecular aza-Michael reaction protocol has been developed for the one-pot synthesis of 1-substituted isoindolines from N-unprotected 2-bromobenzylamines and acrylates with high yields.
A wide range of biaryls were synthesized by palladium-catalyzed Negishi cross-couplings at ambient temperature or with low catalyst loading. This protocol features the use of a recently reported aminobiphenyl palladacycle precatalyst to generate the catalytically active XPhosPd(0) species. Significantly, a wide range of challenging heterocyclic and polyfluorinated aromatic substrates can be emp...
A de novo palladium carbon-catalyzed synthesis of trisubstituted nicotinonitriles from easily synthesized homopropagylic or homoallylic aromatic alcohols in the presence of nitriles has been explored. The mechanism proceeds with an interesting generation of a Pd(II)-C palladacycle followed by an oxidative aromatization to generate the pyridine core. The pyridine core is generated with a notewor...
Buchwald-Hartwig-Migita cross-coupling of 1-thiosugars with α- or β-3-iodo-N-glycosylquinolin-2-ones has been accomplished under mild and operationally simple reaction conditions through the use of a Pd-G3 XantPhos palladacycle precatalyst. This new methodology has been successfully applied to a variety of α- or β-mono-, di-, and poly-thiosugar derivatives to efficiently synthesize a series of ...
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