Visible-Light-driven Synthesis of Phenanthridin-6(5H)-one derivatives through intramolecular C-H Arylation

Colorado, USA

Congreso; ACS Summer School on Green Chemistry & Sustainable Energy; 2023

Phenanthridin-6(5H)-ones are core structures found in various natural products and possess pharmacological properties such as antiviral and antifungal activities. For example, Oxoassosaine has been reported as an antitumor agent.These compounds have been extensively studied, and different methods for their synthesis have been reported. Phenanthridinone rings have been successfully synthesized using palladium salts as catalysts, with different ligands and solvents such as DMF at high temperatures. Other methodologies for the synthesis of these heterocycles involve intermolecular C-N coupling, employing Cu as a catalyst, air as an oxidant, PPh3 as a ligand, and KOtBu as a base in xylene at 120 ºC. Phenanthridinone rings have also been obtained using metal-free methodologies, employing ligands such as vasicine in the presence of KOtBu as a base and high temperatures.Currently, photocatalyzed reactions have proven to be a valuable method for the synthesis of heterocycles and biologically active compounds.6 In 2018, phenanthridinones were successfully synthesized through the intramolecular C-H oxidation of benzamides using the complex Ir[(dCF3ppy)2bpy]PF6 as a photocatalyst.7Due to the biological and pharmacological relevance of these nitrogenous heterocycles, the development of new sustainable synthetic methodologies is necessary. In this work, we present a new methodology for the synthesis of phenanthridinones under mild reaction conditions, using less toxic solvents, a metal-free approach, and at room temperature.