From Aziridines to Daffodils: Development of an Oxidative Insertion for the Synthesis of Isoquinolone Derivatives

In the construction of many natural products, the isoquinolone backbone serves as a challenging functionality to incorporate into a total synthesis. Recent publications have shown that metal-catalyzed intramolecular addition of nitrogen can be achieved with allyl-substituted sulfonamides and carbamates. With this knowledge, we endeavored to provide a new synthetic pathway using dirhodium catalysts, to achieve N-insertion resulting in the desired isoquinolone functionality. Various dirhodium carboxamidate and carboxylate catalysts were efficiently prepared via microwave heating with high yields. Known procedures were adapted for simplified preparations saving time and resources. Results of the oxidative insertion and rearrangement are reported of the benzamide derivatives as well as successful N-H insertion of other benzyl carbamates. While intramolecular aziridination of benzamide derivatives was not achieved, we continue to investigate the oxidative insertion with similar carbamate derivatives