Reactions of phthalans with dienophiles. II. Synthesis of naphthalenes and dihydronaphthalenes by reaction of ethyl maleate and maleic anhydride with 1,1-diethoxyphthalan

Abstract

. Can. J. Chem. 58,2580Chem. 58, (1980. The reactions of I,]-diethoxyphthalan with diethyl maleate and with maleic anhydride have been studied. The reaction with diethyl maleate in a sealed tube gave a mixture of diethyl 1-hydroxynaphthalene-2.3-dicarboxylate and its 0-ethyl derivative. The same reactants at atmospheric pressure gave the ethoxy ester above along with a mixture of isomeric diethyl 1,2-dihydro-1-hydroxy-4-ethoxynaphthalene-2,3-dicarboxylates. The reaction with maleic anhydride gave only diethyl-l-ethoxynaphthalene-2,3-dicarboxylic acid anhydride. These reactions provide further insight into the mechanism of the reaction of phthalans with dienophiles.

Reactions of phthalans with dienophiles. III. Formation of homoquinones by reaction of 1,1-diethoxyphthalans with quinones

“…In two previous papers in this series (1,2) tion that the reaction product was not an anthraphthalans have been shown to react with acetylenic cene derivative. and ethylenic dienophiles to yield substituted naph-…”

“…On a deduit la structure de I'homoquinone a partir de ses spectres (ir, rmn du 'H et du I3C) et on I'a verifik par diffraction de rayons-X. L'homoquinone 3 est triclinique, P I , avec a = 10,601(2), b = 10,434(3), c = 6,491(3)A, a = 105,53(3), P = 95,21 (2), y = 100,66(2)" et deux unites par maille. On a determine la structure du cristal par des methodes directes et on I'a affinee jusqu'i des valeurs de R , = 0,059 et de R 2 = 0,048 en se basant sur 2378 reflexions indkpendantes.…”