The dual-Claisen condensation of diesters with acetoacetate dianion generated tetraoxoalkanedioates, whose aromatization by Ca(OAc)2-promoted intramolecular condensation constructed two carbocyclic rings containing phenol part. The reactions converted glutarates to bicyclic phenols and homophthalates to 1,9-dihydroxy-anthracenes. The latters were air-oxidized to anthraquinones in the presence of K2CO3. The regiochemistry of the arene synthesis was studied. As the products of this synthesis also were glutarates, further extension of the aromatic ring system was carried out. Pentacenequinones were synthesized from anthracenes, while an-thraquinones gave naphthacenequinones. The reactions are related to the biosynthesis of polycyclic aromatic compounds, and arenes obtained are useful intermediates in the natural products synthesis. A formal synthesis of aklavinone was achieved.
ASJC Scopus subject areas
- Organic Chemistry