Michael addition of 4H-cyclopenta[def]phenanthrene to 9,9'-bifluorenylidene and the related reactions.

The compound 9-(4H-cyclopenta[def]phenanthren-4-yl)-9,9′-bifluorene was synthesized by the Michael addition of 4H-cyclopenta[def]phenanthrene to 9,9′-bifluorenylidene and also by other reactions. In addition, five kinds of trimers which consisted of 4H-cyclopenta[def]phenanthrene and fluorene were obtained by the same reactions. The conformation of these trimers is assigned to be the gauche-gauche form.