Star-Shaped Polycyclic Aromatic Ketones via 3-Fold Cycloadditions of Isobenzofuran Trimer Equivalent.

Three-directional annulations of isobenzofuran trimer equivalent are developed. Importantly, the successive cycloadditions could be controlled under suitable conditions, selectively affording the dual or triple cycloadduct, which leads to the alternative preparation of the symmetrical and unsymmetrical star-shaped polycyclic aromatic ketones. 1H NMR analysis of the star-shaped aromatic ketone indicated the π-π interactions through the aggregation in solution.