The reaction between an unfunctionalized conjugated diene and a nitroarene under CO pressure and at 100 degreesC, catalyzed by [Pd(Phen)(2)] [BF4](2) (Phen = 1, 10-phenanthroline), affords the corresponding hetero-Diels-Alder adduct (oxazine) in up to 91% yields in one pot. If the reaction mixture is then heated to 200 degreesC, the oxazines are converted into the corresponding N-arylpyrroles in good yields. Pressures as low as 5 bar can be employed, and 0.08% catalyst is sufficient to effect the transformation. The reaction can be equally run by employing the nitroarene or the diene as limiting agent and works well for nitroarenes bearing either electron-withdrawing or mildly electron-donating substituents. A moderate steric hindrance on the nitroarene (o-methyl) is well tolerated, but 1,4-disubstituted-1,3-dienes are not suitable substrates.

Synthesis of oxazines and N-arylpyrroles by reaction of unfunctionalized dienes with nitroarenes and carbon monoxide, catalyzed by palladium-phenanthroline complexes / F. Ragaini, S. Cenini, D. Brignoli, M. Gasperini, E. Gallo. - In: JOURNAL OF ORGANIC CHEMISTRY. - ISSN 0022-3263. - 68:2(2003), pp. 460-466.

Synthesis of oxazines and N-arylpyrroles by reaction of unfunctionalized dienes with nitroarenes and carbon monoxide, catalyzed by palladium-phenanthroline complexes

F. Ragaini;S. Cenini;M. Gasperini;E. Gallo
2003

Abstract

The reaction between an unfunctionalized conjugated diene and a nitroarene under CO pressure and at 100 degreesC, catalyzed by [Pd(Phen)(2)] [BF4](2) (Phen = 1, 10-phenanthroline), affords the corresponding hetero-Diels-Alder adduct (oxazine) in up to 91% yields in one pot. If the reaction mixture is then heated to 200 degreesC, the oxazines are converted into the corresponding N-arylpyrroles in good yields. Pressures as low as 5 bar can be employed, and 0.08% catalyst is sufficient to effect the transformation. The reaction can be equally run by employing the nitroarene or the diene as limiting agent and works well for nitroarenes bearing either electron-withdrawing or mildly electron-donating substituents. A moderate steric hindrance on the nitroarene (o-methyl) is well tolerated, but 1,4-disubstituted-1,3-dienes are not suitable substrates.
Aromatic carboxylic-acid; C-H functionalization; diels-alder adducts; reductive carbonylation; ruthenium complexes; 1,3-diene synthesis; enyne metathesis; cross-metathesis; bond formation; ethylene
Settore CHIM/03 - Chimica Generale e Inorganica
Article (author)
File in questo prodotto:
File Dimensione Formato  
25) Pd_oxazines.pdf

non disponibili

Tipologia: Publisher's version/PDF
Dimensione 101.58 kB
Formato Adobe PDF
101.58 kB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/187075
Citazioni
  • ???jsp.display-item.citation.pmc??? 1
  • Scopus 50
  • ???jsp.display-item.citation.isi??? 47
social impact