4-Hydroxy-2-pyrones 3, obtained by the condensation reaction of trichlorophenyl malonates 1 with the ketones 2 at 240" C, are rearranged at 260 C via ketenes 6 to yield 1, 3- dihydroxynaphthalenes 5. The latter are readily oxidized to naphthoquinones 4 by air. A side product in the rearrangement of 3 b is triphenylphloroglucinol (7).
[Efremov, Dimitry A.; Zavlin, Pavel M.; Essentseva, Nataly S.; Tebby, John C. Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999), 1994 , # 21 p. 3163 - 3168]
