Asymmetric Total Synthesis of Dankasterones A and B and Periconiastone A Through Radical Cyclization

Abstract We describe herein the assembly of the cis ‐decalin framework through radical cyclization initiated by metal‐catalyzed hydrogen atom transfer (MHAT), further applied it in the asymmetric synthesis of dankasterones A and B and periconiastone A. Position‐selective C−H oxygenation allowed for installation of the necessary functionality. A radical rearrangement was adopted to create 13(14→8) abeo ‐8‐ergostane skeleton. Interconversion of dankasterone B and periconiastone A was realized through biomimetic intramolecular aldol and retro‐aldol reactions. The MHAT‐based approach, serves as a new dissection means, is complementary to the conventional ways to establish cis ‐decalin framework.