نتایج جستجو برای: sonogashira
تعداد نتایج: 591 فیلتر نتایج به سال:
Donor-acceptor phenylene ethynylene systems containing the 6-methylpyran-2-one group, synthesized via classic or microwave-assisted Sonogashira cross-coupling, exhibit pronounced solvatochromism in fluorescence suggesting a highly polar excited state; 4-[4-(4-N,N-dihexylaminophenylethynyl)phenylethynyl]-6-methylpyran-2-one has a fluorescence quantum yield >0.9 in cyclohexane.
One-pot synthesis of highly substituted norbornadienes/norbornenes via gold-catalysed dehydrative cyclisation of alkynyldienols, followed by intermolecular [4 + 2] cycloaddition of in situ generated cyclopentadiene and activated alkynes/alkenes is described. The precursors, alkynyldienols, are obtained via sequential Sonogashira cross-coupling of 3-bromoenals, alkyne addition and reduction. Yie...
A novel heterogeneous transition-metal catalyst comprising a polymer-supported terpyridine palladium(II) complex was prepared and found to promote the Suzuki-Miyaura, Mizoroki-Heck, Sonogashira, and Tsuji-Trost, reactions in water under aerobic conditions with a high to excellent yield. The catalyst was recovered by simple filtration and directly reused several times without loss of catalytic a...
The palladium-catalyzed Sonogashira-type aerobic oxidative coupling of arylhydrazines with terminal alkynes via C-N bond cleavage has been developed; internal alkynes were afforded with a broad substrate scope. This reaction proceeds under copper- and base-free conditions with molecular oxygen as the sole oxidant and nitrogen and water as the only by-products.
An inexpensive synthesis of 6-ethynylbipyridine has been accomplished using Sonogashira coupling of 2-bromo-6-iodopyridine with 2-methyl-3-butyn-2-ol. Subsequent Stille coupling with 2-(trimethylstannanyl) pyridine and hydrolysis provided the target compound in an overall high yield.
A new synthesis of 4-halo-1H-indoles has been developed from easily available 2,3-dihalophenol derivatives. The key steps are Smiles rearrangement and a one-pot or stepwise Sonogashira coupling/NaOH-mediated cyclization. Subsequent functionalization allows access to a wide variety of 2,4- or 2,3,4-regioselectively functionalized indoles.
Based on consecutive one-pot conditions combining three palladium-catalyzed reactions (Sonogashira, Heck and Suzuki-Miyaura reactions), a more efficient domino multicomponent method has been successfully developed to access a wide variety of 3-(diarylmethylene)oxindoles. Microwave irradiation and use of a silver salt were the most important factors to achieve high yields and stereoselectivity.
Reactions of 10-benzo[h]quinolyllithium with a series of organosilanes led to the formation of neutral pentacoordinate complexes. The diethynyl-substituted complex was able to be converted to di(arylethynyl)-substituted ones by the Sonogashira-Hagihara coupling reaction. Electronegative substituents shortened N-Si distances and enhanced fluorescence intensity from the complexes.
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