An Enantioselective Formal Synthesis of Berkelic Acid
摘要:
An enantioselective formal synthesis of berkelic acid is described. The key step Involves a late-stage silyl enol ether addition to a benzannulated oxonium ion with subsequent spiroketalization leading to construction of the tetracyclic core. Thermodynamically controlled equilibration under acidic conditions affords the desired spiroketal configuration as a single diastereoisomer.