Organocalcium-mediated nucleophilic alkylation of benzene

• Autor: Wilson, Andrew S. S. ; Hill, Michael S. ; Mahon, Mary F. ; Dinoi, Chiara ; Maron, Laurent
• Assuntos: Alkylation ; Benzene ; Calcium ; Carbon compounds ; Chemical Sciences ; Chemical synthesis ; Density functional theory ; Ethene ; Ethylene ; Hydrocarbons ; Hydrogen bonds ; Lithium ; Magnesium ; Mineralogy ; Nucleophiles ; Organic chemistry ; Physics ; Regeneration ; Substitution reactions
• É parte de: Science (American Association for the Advancement of Science), 2017-12, Vol.358 (6367), p.1168-1171
• Notas: ObjectType-Article-1
  SourceType-Scholarly Journals-1
  ObjectType-Feature-2
  content type line 23
  
• Descrição: The electrophilic aromatic substitution of a C–H bond of benzene is one of the archetypal transformations of organic chemistry. In contrast, the electron-rich π-system of benzene is highly resistant to reactions with electron-rich and negatively charged organic nucleophiles. Here, we report that this previously insurmountable electronic repulsion may be overcome through the use of sufficiently potent organocalcium nucleophiles. Calcium n-alkyl derivatives—synthesized by reaction of ethene, but-1-ene, and hex-1-ene with a dimeric calcium hydride—react with protio and deutero benzene at 60°C through nucleophilic substitution of an aromatic C–D/H bond. These reactions produce the n-alkyl benzenes with regeneration of the calcium hydride. Density functional theory calculations implicate an unstabilized Meisenheimer complex in the C–H activation transition state.
  
• Editor: United States: American Association for the Advancement of Science
  
• Idioma: Inglês