Synthesis and Diels?Alder Reactivity of ortho-Carbazolequinones.

Oxidation of 2- and 3-hydroxycarbazoles with Fremy's salt gave the corresponding ortho-carbazolequinones. These molecules react as carbodienophiles in Diels-Alder reaction with 1-acetoxy-1,3-butadiene and 1,3-cyclopentadiene to provide the novel benzocarbazolequinone structures 15, 16, 18 and 19.