The Preparation and Reactions of Naphthofuran and Naphthofuran

Article abstract of DOI:10.1021/jo00370a004

The syntheses of 1,3-dihydro-1- and 1,3-dihydro-3-hydroxynaphtho<1,2-c>furan are described.Upon treatment with acid, these compounds undergo 1,4-elimination of water to generate the reactive naphtho<1,2-c>furan, which is trapped in situ by a variety of dienophiles.Aromatization of the resulting adducts gives access to 2,3-disubstituted phenanthrenes or benzanthracenes.In addition, it has been shown that the hemiacetal, 1,3-dihydro-1-hydroxynaphtho<2,3-c>furan, which exists in tautomeric equilibrium with 3-(hydroxymethyl)-2-naphthaldehyde, serves as a convenient source of naphtho<2,3- c>furan.This furan can also be trapped by a variety of dienophiles.The resulting Diels-Alder adducts can be aromatized, giving substituted anthracenes.The use of aromatic 1,4-quinones as dienophiles leads to linear polycyclic aromatic quinones of four to seven rings.