Synthesis of azafluorenones and related compounds using deprotocupration-aroylation followed by intramolecular direct arylation

Nada Marquise (1) , Philip J. Harford (2) , Floris Chevallier (1) , Thierry Roisnel (1) , Vincent Dorcet (1) , Anne-Laure Gagez (3) , Sophie Sablé (3) , Laurent Picot (3) , Valérie Thiéry (3) , Andrew E. H. Wheatley (2) , Philippe C. Gros (4) , Florence Mongin (1)

1 ISCR - Institut des Sciences Chimiques de Rennes
2 Department of Chemistry
3 LIENSs - LIttoral ENvironnement et Sociétés
4 SRSMC - Structure et Réactivité des Systèmes Moléculaires Complexes

The efficiency of the deprotocupration-aroylation of 2-chloropyridine using lithiocuprates prepared from CuX (X=Cl, Br) and LiTMP (TMP=2,2,6,6-tetramethylpiperidido, 2 equiv) was investigated. CuCl was identified as a more suitable copper source than CuBr for this purpose. Different diaryl ketones bearing a halogen at the 2 position of one of the aryl groups were synthesized in this way from azines and thiophenes. These were then involved in palladium-catalyzed ring closure: substrates underwent expected CH-activation-type arylation to afford fluorenone-type compounds, and were also subjected to cyclization reactions leading to xanthones, notably in the presence of oxygen-containing substituents or reagents.

Mots clés: Deprotometalation; Copper; Lithium; Heterocycle; Palladium

Domaines: Autre

Nada Marquise, Philip J. Harford, Floris Chevallier, Thierry Roisnel, Vincent Dorcet, et al.. Synthesis of azafluorenones and related compounds using deprotocupration-aroylation followed by intramolecular direct arylation. Tetrahedron, 2013, 69 (47), pp.10123-10133. ⟨10.1016/j.tet.2013.09.030⟩. ⟨hal-00869376⟩