Intermolecular Benzyne Cycloaddition (IBC), a Versatile Approach to Benzophenanthridine Antitumor Alkaloids. Formal Synthesis of Nitidine and Chelerythrine

Article abstract of DOI:10.1021/jo00048a024

A new approach to the synthesis of benzophenanthridine alkaloids is described which is based on cycloaddition of arynes to pyrrolinediones, the pyrrolinediones behaving as aza diene equivalents.The synthesis of 2,3,8,9-substituted benzophenanthridines and the regioselective synthesis of a 2,3,7,8-substituted benzophenanthridine were performed.The formal synthesis of chelerythrine and the antitumor alkaloid nitidine is described.