THERMAL CYCLOADDITION REACTIONS OF 3-BROMO-1,5-AZULENEQUINONE AND 3-BROMO-1,7-AZULENEQUINONE WITH 1,3-DIPHENYLBENZO[C]FURAN

With 1,3-diphenylbenzo[c]furan, 3-bromo-1,5-azulenequinone afforded 1: 1- and 1:2-cycloadducts, two [2+4] cycloadducts and two [2+4]-[2+4] cy cloadducts which were isolated as the rearrangement products. However, 3-bromo-1,7-azulenequinone was less reactive to form only two 1:2-cyc loadducts, [2+4]-[6+4] products, in low yields. The structures of key products from both quinones were solved by X-ray diffraction analysis.