Temporary Intramolecular Generation of Pyridine Carbenes in Metal-Free Three-Component C-H Bond Functionalisation/Aryl-Transfer Reactions - Aix-Marseille Université Accéder directement au contenu
Article Dans Une Revue Chemistry - A European Journal Année : 2013

Temporary Intramolecular Generation of Pyridine Carbenes in Metal-Free Three-Component C-H Bond Functionalisation/Aryl-Transfer Reactions

Faisal Nawaz
  • Fonction : Auteur
Kishor Mohanan
  • Fonction : Auteur
Laurence Charles
Michel Rajzman
  • Fonction : Auteur
Damien Bonne
Olivier Chuzel
Jean Rodriguez
  • Fonction : Auteur
  • PersonId : 921781
Yoann Coquerel

Résumé

Nucleophilic addition of pyridines to benzyne generates zwitterionic adducts that evolve by a rapid intramolecular proton shift to produce the corresponding pyridine carbenes, N-phenyl pyrid-2-ylidenes. In the presence of electrophilic ketones (isatin derivatives), the pyridylidenes can further react by an original bis-arylation reaction of the carbonyl compounds involving a formal pyridine C-H bond functionalisation. The overall transformation is an unprecedented three-compo- nent reaction featuring a carbene intermediate. The mechanism of this transformation was examined in detail by using both experimental and theoretical approaches. It was found that the generation of N-phenyl pyrid-2-ylidene from pyridine and benzyne is energetically favoured, and that the corresponding carbene dimer can also form easily. Under the three-component reaction conditions, the pyridylidene preferentially adds to the ketone group of the isatin derivative to produce a zwitterionic adduct amenable to an intramolecular aryl transfer reaction by a concerted nucleophilic aromatic substitution. This peculiar reactivity for a carbene was compared to possibly competitive known reactions of stable carbenes with carbonyl compounds, and the reaction was found to be under thermodynamic control. The reported method of generation of N-phenyl pyrid-2-ylidenes and their reactivity with carbonyl compounds unlock new perspectives in organic synthesis.

Domaines

Chimie organique

Dates et versions

hal-00979202 , version 1 (15-04-2014)

Identifiants

Citer

Faisal Nawaz, Kishor Mohanan, Laurence Charles, Michel Rajzman, Damien Bonne, et al.. Temporary Intramolecular Generation of Pyridine Carbenes in Metal-Free Three-Component C-H Bond Functionalisation/Aryl-Transfer Reactions. Chemistry - A European Journal, 2013, 19 (51), pp.17558-17583. ⟨10.1002/chem.201303359⟩. ⟨hal-00979202⟩
51 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More