A novel approach to ring A analogues of the marine pyridoacridine alkaloid ascididemin

A novel approach to ring A analogues of the marine pyridoacridine alkaloid ascididemin starting from readily available 4-bromobenzo[c][2,7]naphthyridine (10) comprises a high-yield Minisci-type homolytic methoxycarbonylation at C-5, followed by introduction of the ring A scaffold via Suzuki cross-coupling reaction, and a trifluoromethanesulfonic acid-aided Friedel–Crafts-type intramolecular acylation. This protocol allows for the introduction of various electron-rich carbocyclic and heterocyclic ring A substitutes.