TfOH-Mediated Cascade Cyclization of Conjugated Enynes to Access Benzofluorenones

Benzofluorenones are significant molecular entities, constituting a wide variety of compounds of diverse applications. This report describes the rapid construction of benzofluorenone scaffolds through the acid-mediated cascade cyclization of easily accessible precursors with a 1,5-enyne conjugated system. The strategy exhibits a broad substrate scope, yielding products with distinct structural features. Additionally, several postsynthetic modifications were carried out, demonstrating the versatility and effectiveness of this approach in generating complex molecular architectures. Solvatochromism studies have also been conducted.