نتایج جستجو برای: heck cross coupling
تعداد نتایج: 633215 فیلتر نتایج به سال:
The reaction of Hg(CF3CO2)2 with metalloporphyrins produces mercurated porphyrins regioselectively, the reaction, surprisingly occurring at the most hindered betaB-position; this behavior is in marked contrast to the usual electrophilic substitution reactions of porphyrins, whose reactions produce meso-substituted porphyrins; the obtained mercurated porphyrins are active to transition metal-cat...
Substituted azafluorenones were synthesized from different dihalogeno diaryl ketones under palladium catalysis by combining either Suzuki or Heck coupling with direct cyclizing arylation. Conditions were identified to allow both auto-tandem processes to proceed successfully from 3-(bromobenzoyl)- or 3-benzoyl-4-bromo-2-chloropyridines, as well as 4-benzoyl-2,3- and 4-benzoyl-2,5-dichloropyridines.
A variety of 2-hydroxy aldehydes on reaction with 3-butenoic acid afford in a one-pot reaction the corresponding 3-vinylcoumarins. As expected, extension of the delocalized π-electron system accomplished by Heck coupling reactions with aryl halides results in an increased fluorescence of the compounds whose applicability is yet to be established.
Heck reaction catalyzed by cobalt hollow nanospheres has been developed; the coupling of alkenes with aryl iodide or aryl bromide in the presence of potassium carbonate provides the corresponding products with moderate to good yields, which reveals obvious advantages such as low-cost catalyst, ligand-free condition, the recyclability of the catalyst and simple experimental operation.
The synthesis of a new 2,2'-bipyridyl functionalized oligovinylenephenylene (OVP-5) containing a methyl protected thiol using Heck coupling and the Horner-Wadsworth-Emmons reaction and is described. A key step involving a diisopropylcarbodiimide promoted dehydration of a stable β-hydroxyphosphonate intermediate was identified. The structure of precursor E-(4-(4-bromostyryl)phenyl)(methyl)sulfan...
[reaction: see text] An efficient and versatile method for stereoselective synthesis of (E)-3,3-(diarylmethylene)indolinones by a palladium-catalyzed tandem Heck-carbocyclization/Suzuki-coupling sequence is presented. Factors influencing yield and selectivity, namely catalyst, coordinating ligand, and solvent, are detailed.
Intermolecular Heck reaction of common alkyl halides, a longstanding problem in palladium catalysis, is realized with a simple Pd/dppf catalyst. Both primary and secondary alkyl halides are suitable for coupling with aromatic olefins. Single electron transfer from (dppf)Pd(0) to alkyl halide initiated the catalytic cycle and gave alkyl radicals.
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