CYCLOCONDENSATIONS OF HOMOPHTHALIC ANHYDRIDES WITH 1-AZA-1,3-DIENES

alpha,beta-Unsaturated aldimines (1-aza-1,3-butadienes) 2, 4 and 7a-d react with homophthalic anhydrides 1a,b to give 3,4-dihydro-1(2H)-naph thalenone-4-carboxylic acids 3, 5, 8a-d(R(2) = H) as main products. Ho mophthalic anhydride 1a and cinnamaldimine 7d gave rise to the diaster eoisomeric naphthalenones 8d (R(2) = H), along with the 3,4-dihydro-1( 2H)-isoquinolinone-4-carboylic acids 10 (R(2) = H), and 3,4-dihydro-1( 2H)-pyridinone 11 (R(2) = H) as products of 3,4-, 1,2- and 1,4-additio n to the 1-aza-1,3-butadiene, respectively. The effect of the reaction conditions on the ratio of adducts, produced by la and 7d, was studie d. The structure and relative configurations of 3, 5, 8a-d, 10 and 11 were determined by NMR spectroscopy. In the case of cis-naphthalenone 8c and dihydropyridinone 11, the structure was confirmed by X-ray crys tal structure analysis.