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- Ullmann_reaction abstract "The Ullmann reaction or Ullmann coupling is a coupling reaction between aryl halides with copper. The reaction is named after Fritz Ullmann, who derived it from a reaction developed by his wife, Irma Goldberg. A typical example is the coupling of 2 o-chloronitrobenzene reactants to form 2,2'-dinitrobiphenyl with a copper - bronze alloy.The traditional version of the Ullmann reaction requires harsh reaction conditions, and the reaction has a reputation for erratic yields. Since its discovery some improvements and alternative procedures have been introduced.The reaction mechanism of the Ullmann reaction is extensively studied. Electron spin resonance rules out a radical intermediate. The oxidative addition / reductive elimination sequence observed with palladium catalysts is unlikely for copper because copper(III) is rarely observed. The reaction probably involves the formation of an organocopper compound (RCuX) which reacts with the other aryl reactant in a nucleophilic aromatic substitution. Alternative mechanisms do exist such as σ-bond metathesis.The classical Ullmann reaction is limited to electron deficient aryl halides and requires harsh reaction conditions. Modern variants of the Ullman reaction employing palladium and nickel have widened the substrate scope of the reaction and rendered reaction conditions more mild. Yields are generally still moderate, however. In organic synthesis this reaction is often replaced by palladium coupling reactions such as the Heck reaction, the Hiyama coupling and the Sonogashira coupling.In a variation of the Ullmann reaction, (2-bromovinyl)-benzene is reacted with imidazole in an ionic liquid, BMIMBF4*, to give N-(2-phenylvinyl)-imidazole. The reaction requires (L)-proline catalysis.".
- Ullmann_reaction thumbnail Ullmann_reaction.svg?width=300.
- Ullmann_reaction wikiPageID "2214609".
- Ullmann_reaction wikiPageRevisionID "600943095".
- Ullmann_reaction hasPhotoCollection Ullmann_reaction.
- Ullmann_reaction subject Category:Carbon-carbon_bond_forming_reactions.
- Ullmann_reaction subject Category:Condensation_reactions.
- Ullmann_reaction subject Category:Name_reactions.
- Ullmann_reaction type ChemicalProcess113446390.
- Ullmann_reaction type ChemicalReaction113447361.
- Ullmann_reaction type CondensationReactions.
- Ullmann_reaction type NameReactions.
- Ullmann_reaction type NaturalProcess113518963.
- Ullmann_reaction type PhysicalEntity100001930.
- Ullmann_reaction type Process100029677.
- Ullmann_reaction comment "The Ullmann reaction or Ullmann coupling is a coupling reaction between aryl halides with copper. The reaction is named after Fritz Ullmann, who derived it from a reaction developed by his wife, Irma Goldberg. A typical example is the coupling of 2 o-chloronitrobenzene reactants to form 2,2'-dinitrobiphenyl with a copper - bronze alloy.The traditional version of the Ullmann reaction requires harsh reaction conditions, and the reaction has a reputation for erratic yields.".
- Ullmann_reaction label "Accoppiamento di Ullmann".
- Ullmann_reaction label "Reakcja Ullmanna".
- Ullmann_reaction label "Réaction d'Ullmann".
- Ullmann_reaction label "Ullmann reaction".
- Ullmann_reaction label "Ullmann-Reaktion".
- Ullmann_reaction label "Ullmann-reactie".
- Ullmann_reaction label "ウルマン反応".
- Ullmann_reaction label "乌尔曼反应".
- Ullmann_reaction sameAs Ullmann-Reaktion.
- Ullmann_reaction sameAs Réaction_d'Ullmann.
- Ullmann_reaction sameAs Accoppiamento_di_Ullmann.
- Ullmann_reaction sameAs ウルマン反応.
- Ullmann_reaction sameAs Ullmann-reactie.
- Ullmann_reaction sameAs Reakcja_Ullmanna.
- Ullmann_reaction sameAs m.06wht6.
- Ullmann_reaction sameAs Q904703.
- Ullmann_reaction sameAs Q904703.
- Ullmann_reaction sameAs Ullmann_reaction.
- Ullmann_reaction wasDerivedFrom Ullmann_reaction?oldid=600943095.
- Ullmann_reaction depiction Ullmann_reaction.svg.
- Ullmann_reaction isPrimaryTopicOf Ullmann_reaction.