Stereoselective total syntheses of (−)-hygrophorone A12, 4-O-acetyl-hygrophorone A12 and (+)-hygrophorone B12

Abstract

Total syntheses of anti-fungal cyclopentenones (−)-hygrophorone A¹², 4-O-acetyl-hygrophorone A¹² and (+)-hygrophorone B¹² were achieved in high overall yields from D-(−)-tartaric acid. The key feature of these syntheses is the aqueous KOH-mediated diastereoselective intramolecular aldol reaction to form β-hydroxy ketone with three contiguous chiral centres, which was further elaborated to (−)-hygrophorone A¹² and (+)-hygrophorone B¹². The synthetic route reported here is operationally simple and highly diastereoselective and is amenable for the synthesis of several analogues of hygrophorones.