Thermal cycloaddition reactions of azulene-1,5-quinones and azulene-1,7-quinones with cyclic dienes and cycloheptatriene

[2+4]-[6+4] Cycloadducts were obtained from the thermal cycloaddition react ions of azulenequinones with cyclic 4 pi systems such as 1,3-diphenylisoben zofuran and isobenzofuran while the reaction of cycloheptatriene and azulen equinones gave ene products as well as cage molecules. The first addition s ite of 1,3-diphenylisobenzofuran was different for 3-bromoazulene-1,5-quino ne and azulene-1,5-quinone; the former reacted on the cyclopentenone part a nd the latter on the C-6-C-7 bond to avoid formation of an unstable cyclope ntadienone structure.