Expeditious Synthesis of the Topoisomerase I Inhibitors Isoindolo-[2,1-b]isoquinolin-7(5H)-one and the Alkaloid Rosettacin Based on Aryl Radical Cyclization of Enamide Generated by Using N-Acyl-iminium Chemistry

A short and effective approach to the synthesis of the topoisomerase I inhibitor isoindolo[2,1-b] isoquinolin-7(5H)-one and the alkaloid rosettacin belonging to the aromathecin family is presented. The key step of this sequence, which resulted in the formation of a five-membered ring, was the aryl radical cyclization of enamides generated using N-acyliminium chemistry.