نتایج جستجو برای: sonogashira
تعداد نتایج: 591 فیلتر نتایج به سال:
Immobilized Pd-complexes allowed macrocyclisations via the Tsuji-Trost-reaction in concentrated solutions. Systematic studies suggest that the origin of this pseudodilution effect is neither film diffusion nor gel diffusion, but the reduction in conformational freedom of intermediates and intramolecular prenucleophile activation. In contrast a pseudodilution effect could not be observed for Son...
Conditions for an efficient ligand-, copper-, and amine-free palladium-catalyzed Sonogashira reaction of aryl iodides and bromides with terminal alkynes have been developed. Critical to the success of this new protocol is the use of tetrabutylammonium acetate as the base. Noteworthy features of this method are room-temperature conditions and the tolerance of a broad range of functional groups i...
Polysilane-supported Pd and Pt catalysts have been prepared for the first time, and used successfully in hydrogenation, Suzuki and Sonogashira reactions, and hydrosilylation respectively: the reactions proceeded in high yields, and the catalysts could be recovered almost quantitatively by simple filtration and reused.
A microwave-enhanced, rapid and efficient homogeneous-phase version of the Sonogashira reaction is presented. It has been applied to the coupling of aryl iodides, bromides, triflates, and aryl chloride, as well as pyridine and thiophene derivatives with trimethylsilylacetylene. Excellent yields (80-95%) for substrates containing a large variety of substituents in different positions are obtaine...
An eumelanin-inspired core derived from the natural product, vanillin (vanilla bean extract) was utilized for the synthesis of eumelanin-inspired small molecules and polymer via Sonogashira cross coupling. The materials demonstrate that the methyl 4,7-dibromo-5,6-dimethoxy-N-methyl-1H-indole-2-carboxylate core can serve as a new building block for organic semiconductors.
A low pressure microflow system was developed for palladium-catalyzed multiphase carbonylation reactions in an ionic liquid. The microflow system resulted in superior selectivity and higher yields in carbonylative Sonogashira coupling and amidation reactions of aryl iodides compared to the conventional batch system.
One-pot synthesis of symmetric 1,4-disubstituted 1,3-diynes from iodoarenes and propiolic acid via Sonogashira reaction followed by Pd-catalyzed decarboxylative homocoupling is developed in high yields. Also, this system allows the one-pot synthesis of unsymmetric 1,4-disubstituted 1,3-diynes by cross-coupling of two different 3-substituted propiolic acids.
A systematic study into the Sonogashira cross-coupling of 1,1'-diiodoferrocene (fcI2) confirms that the Pd(0)-P((t)Bu)3 system provides a remarkable rate increase over Pd(0)-(PPh3)2. Attempts to couple 4-ethynylphenylthioacetate (2) with fcI2 instead produced a novel cyclic trimer of the former, from syn addition of S-Ac across C≡C.
Herein, we report on our findings of the Sonogashira-Hagihara reaction with 1-iodinated and 2-brominated glycals using several aromatic and aliphatic alkynes. This Pd-catalyzed cross-coupling reaction presents a facile access to alkynyl C-glycosides and sets the stage for a reductive/oxidative refunctionalization of the enyne moiety to regenerate either C-glycosidic structures or pyran derivati...
Recent developments concerning the application of polymer supported organometallic reagents in solid phase synthesis are reviewed, with a special focus on methodology for carbon-carbon formation. Examples of reactions that are covered include the classical Suzuki, Sonogashira and Heck coupings, but also aryl amination, epoxide opening, rearrangements, metathesis and cyclopropanation. Applicatio...
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