Phosphoric Acid‐Catalyzed Enantioselective Synthesis of Axially Chiral Anthrone‐based Compounds

Anthrones and analogues are structural cores shared by diverse pharmacologically active natural and synthetic compounds. The sp2‐rich nature imposes inherent obstruction to introduce stereogenic element onto the tricyclic aromatic backbone. In our pursuit to expand the chemical space of axial chirality, a novel type of axially chiral anthrone‐derived skeleton was discovered. This work establishes oxime ether as suitable functionality to furnish axial chirality on symmetric anthrone skeletons through stereoselective condensation of the carbonyl entity with long‐range chirality control. The enantioenriched anthrones could be elaborated into dibenzo‐fused seven‐membered N‐heterocycles containing well‐defined stereogenic center via Beckmann rearrangement with axial‐to‐point chirality conversion.