One‐Pot Synthesis of Phenanthridinones by Using a Base‐Catalyzed/Promoted Bicyclization of α,β‐Unsaturated Carbonyl Compounds with Dimethyl Glutaconate

A new strategy for the highly efficient construction of functionalized phenanthridinones has been developed by starting from readily available acyclic α,β‐unsaturated carbonyl compounds that have a 2‐aminophenyl group at the β‐position or carbonyl carbon and dimethyl glutaconate. The domino reaction involves an intermolecular [3+3] annulation followed by an intramolecular aza‐cyclization/aromatization process and allows for the synthesis of polysubstituted dihydrophenanthridinone and phenanthridinone derivatives in high to excellent yields under extremely mild conditions (i.e., transition‐metal‐free and open to air) in a single step.