Palladium(0)-catalyzed cyclization of 1,6-diyn-3-yl carbonates with a nucleophilic functionality: efficient synthesis of polycyclic benzo[b]fluorene derivatives via allene intermediates.

We report in this paper an interesting tandem reaction involving sequential palladium(0)-catalyzed decarboxylation of diynylic carbonates, intramolecular nucleophilic cyclization and Schmittel reaction, which provides a facile method for the synthesis of a variety of polycyclic benzo[b]fluorene derivatives from easily accessible starting materials.