Highly Substituted Acephenanthrylenes and Their π-Extended Derivatives: Syntheses, Structural Analyses, and Properties.

This investigation demonstrates that a series of (highly) substituted acephenanthrylenes (APs) , benzo[]acephenanthrylene , and dicyclopenta[,]pyrene are easily prepared by palladium-catalyzed cycloaromatization of 2,3-diethynylbiphenyls . The first nonpyrolysis synthesis of by two-fold cycloaromatization was achieved in a high yield. This synthetic protocol has two crucial advantages: facile introduction of various substituents and efficient extension of the AP backbone.