Spiroxins A-E, isolated from a marine-derived fungus, have a unique octacyclic bisnaphthospiroketal structure. Spiroxin A was reported to show antibacterial and antitumor activities, both of which are thought to be caused by DNA cleavage. We previously reported the first total synthesis of (±)-spiroxin C, which included TBAF-activated Suzuki-Miyaura cross-coupling reaction and an intramolecular bromoetherification reaction as key reactions. Here, we applied the synthetic strategy to that of spiroxin A having additional two functional groups, hydroxyl group and chlorine. Starting from 5, 8-dihydroxy-1-tetralone, we successfully synthesized a key intermediate for spiroxin A by utilizing the above key reactions and regioselective chlorination. Remaining steps to complete the synthesis are under investigation.
