Anagram & Information om | Engelska ordet YLIDE

Exempel på hur man kan använda YLIDE i en mening

• The Wittig reaction or Wittig olefination is a chemical reaction of an aldehyde or ketone with a triphenyl phosphonium ylide called a Wittig reagent.
• Nevertheless, the contemporary discoveries of the first diphosphorus ylide and first phosphaalkene suggested that compounds with multiply-bonded phosphorus could be made.
• The aminopyrimidine ring on TPP acts as a base, once in its imine form, to pull off the C2 proton from TPP to form the nucleophile ylide.
• The Corey–Fuchs reaction is based on a special case of the Wittig reaction, where two equivalents of triphenylphosphine are used with carbon tetrabromide to produce the triphenylphosphine-dibromomethylene ylide.
• The reaction involves addition of a sulfur ylide to a ketone, aldehyde, imine, or enone to produce the corresponding 3-membered ring.
• If Y is nitrogen, the reaction is referred to as the Sommelet–Hauser rearrangement if a quaternary ammonium salt is involved or the aza-Wittig reaction if an alpha-metalated tertiary amine is involved; if Y is oxygen, then it is called a 2,3-Wittig rearrangement (not to be confused with the well-known Wittig reaction, which involves a phosphonium ylide).
• The ylide is prepared in situ by reaction of the diazo compound ethyl diazomalonate with a sulfide catalyzed by dirhodium tetraacetate in refluxing xylene.
• This was initially thought to be an aromatic ylide, but is now believed to be a carbene In the presence of a strong electrophile, such as an aldehyde or ketone, this species will undergo nucleophilic attack faster than proton transfer.
• His seminal discoveries in this area ranged from tetracyanoethylene oxide, which adds to olefins through its carbon-carbon bond; hexacyanobutadiene, with an oxidation potential near that of bromine; pentacyanocyclopentadiene, an acid as strong as perchloric acid; diiminosuccinonitrile, a remarkable adduct of cyanogen and hydrogen cyanide; and diazodicyanoimidazole, which cleaves to a carbene that forms a bromo ylide with bromobenzene.
• A secondary amine was combined with an aldehyde to form an intermediate azomethine ylide, which underwent a 1,3-dipolar cycloaddition with an unsaturated oxindole also present in the reaction mixture.
• Coldham's research areas include the intramolecular trapping of episulfonium ions with amine nucleophiles, the use of triisopropylsilyl enol ethers in organic synthesis, chiral organolithium chemistry, azomethine ylide cycloaddition, and natural product synthesis.
• The addition of at least two equivalents of base deprotonates the alkoxysulfonium ion to give sulfur ylide 7 and removes the pyridinium sulfate counterion.
• As resonance structures 1c and 1d become more important the nitrilium ylide distorts its geometry from linear in favor of a different valence tautomer 2 that is distinctly bent:.
• The azomethine ylide reactivity of münchnones, and their reaction with alkynes in the synthesis of pyrroles, was first published by Huisgen et al.
• To obtain the ylide needed, firstly triphenyl phosphine is reacted with ethyl bromoacetate to form a phosphonium salt; after treatment of this salt with a mild base, the ylide can be reacted with the aldehyde in toluene.
• The Banwell group’s synthesis of lamellarin K includes an intramolecular azomethine ylide cyclization.
• Theoretical and experimental analysis of stable montréalones reveals overlapping azomethine ylide and Wittig-type moieties within the unsaturated 5-membered organophosphorus ring system.
• Initial research utilised sulfur ylide linkers, but more recently the group developed acid- and photo-labile ketoacid monomers that can be loaded directly on Rink Amide resin.
• Scorrano, he published the first paper on the azomethine ylide cycloaddition to C60, which resulted to be a very useful reaction of functionalization of fullerenes.
• In their paper, upon introducing CO, metalated ylide with posassium cation exchange CO with phosphine group R, also known for carbonylation of ylide.

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