نتایج جستجو برای: 3 dipolar cycloaddition
تعداد نتایج: 1820449 فیلتر نتایج به سال:
Ultrasound irradiation can promote the 1,3-dipolar cycloaddition reaction of 2-chloropyridinium ylides with 2-benzylidenemalononitrile or 2,2'-(1,4-phenylenebis(methanylylidene))dimalononitrile, to afford the indolizine and bis-indolizine derivatives respectively. While the reaction of pyridinium ylides with 2-benzylidenemalononitrile or 2,2'-(1,4-phenylenebis(methanylylidene))dimalononitrile u...
[reaction: see text] A general strategy for highly enantioselective 1,3-dipolar cycloaddition of diazoesters to beta-substituted, alpha-substituted, and alpha,beta-disubstituted alpha,beta-unsaturated pyrazolidinone imides is described. Cycloadditions utilizing less reactive alpha,beta-disubstituted dipolarophiles require elevated reaction temperatures, but still provide the corresponding pyraz...
Computational chemistry is used to study a 1,3-dipolar cycloaddition between an azide and an alkyne inside the macrocycle cucurbit[6]uril, in order to elucidate the catalytic function of a highly efficient supramolecular catalyst.
Trifluoromethylated pyrrolidines have been synthesized via catalytic asymmetric 1,3-dipolar cycloaddition with excellent stereoselectivity for the first time. Epimerization of the endo-pyrrolidines obtained from cis-4,4,4-trifluorocrotonate into the exo-pyrrolidines was also revealed.
The novel multicomponent reaction of [60]fullerene with dimethyl acetylenedicarboxylate and isoquinoline, quinoline or substituted quinolines was investigated. This type of reaction presents the first example of a 1,4-dipolar cycloaddition reaction in fullerene chemistry.
A chiral phosphoric acid-catalyzed intramolecular 1,3-dipolar cycloaddition of 4-(2-formylphenoxy)butenoates with amino esters provides hexahydromeno[4,3-b]pyrrolidine derivatives in high enantioselectivity (up to 94% ee).
The yield and enantioselectivity of an asymmetric aldol reaction, catalyzed by a proline derivative immobilized on polystyrene via dipolar cycloaddition, are remarkably improved by the dendronization of the support.
Mono- and diglycosylated aromatics and heteroaromatics may serve as building blocks for the construction of metabolically stable mimetics of oligosaccharides. Methods for their preparation from monosaccharidic precursors by direct C-glycosylation, dipolar cycloaddition or Larock cyclization are described.
A direct and facile synthesis of highly functional 5-aza-spiro[2,4]heptanes, a valuable structural motif for drug discovery, is developed via catalytic asymmetric 1,3-dipolar cycloaddition of cyclopropylidene acetate and azomethine ylides for the first time.
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