. Can. J. Chem. 63, 3526 (1985). Previous work from our laboratory has been concerned with investigating the photochemical reactivity of the tetrahydro-1,4-napthalenedione system, both in solution and the solid state. The results obtained prompted us to extend our studies to the analogous tetrahydro-l,4-anthracenedione system. The most direct method of synthesis of the desired compounds is through Diels-Alder addition of o-quinodimethane to p-quinones. Because of the ease with which the adducts would be expected to undergo bis-enolization to the corresponding hydroquinones, their preparation requires mild, neutral conditions. After much experimentation, success was achieved using the Durst-Charlton sulfur dioxide extrusion method for generating o-quinodimethane from 3,6-dihydro-l,2-oxathiin-2-oxide. In situ trapping.using p-benzoquinone and other substituted p-quinones afforded the desired adducts in reasonable yields. In the case of duroquinone and 2,3-dimethyl-l,4-naphthalenedione, fluoride ion-catalyzed generation of o-quinodimethane from [o-[cu-(trimethylsilyl)methyl]benzyl]trimethylamrnoniurn bromide by the method of Ito also gave acceptable results; however, the bis-enolizable adducts were not stable under these eaction conditions. SYED ASKARI, SUSAN LEE, ROBERT R. PERKINS et JOHN R. SCHEFFER. Can. J. Chem. 63, 3526 (1985). Dans un travail anttrieur rtalist dans notre laboratoire, on a examine la rtactivitt photochimique du systeme titrahydronaphtalbnedione-1,4 tant en solution qu'a l'ttat solide. Les rtsultats obtenus nous ont incitt a Ctendre nos ttudes au systbrne analogue de la tttrahydroanthracenedione-1,4. La rntthode la plus directe de synthese des composts dtsirts implique une addition de Diels-Alder du o-quinodimtthane sur des p-quinones. Compte tenu du fait qu'il est A prCvoir que les adduits subiront facilement une bis-enolisation conduisant aux hydroquinones correspondantes, il est important d'utiliser des conditions