K. Kobayashi et al., A DIRECT ONE-POT PREPARATION OR NAPHTHO[2,3-B]FURAN-4,9-DIONES FROM 2-HYDROXY-1,4-NAPHTHOQUINONES AND ENAMINES, Synthesis, (9), 1998, pp. 1243-1245
The reaction of 2-hydroxy-1,4-naphthoquinones with enamines, derived f
rom ketones, in refluxing toluene afforded the corresponding 2,3-disub
stituted naphtho[2,3-b]furan-4,9-dione derivatives in moderate to good
yields.