Total synthesis of (S)‐(+)‐ent‐phomapyrones B and surugapyrone B

Abstract Phomapyrone B ( 1 ), the 2‐pyrones isolated from the phytopathogenic fungus Leptosphaeria maculans , has been synthesized as the enantiomeric form starting from ( S )‐2‐methylbutanol ( 4 ). Surugapyrone B ( 3 ) isolated from Streptmyces sp. USF‐6280 as an antioxidant has also been synthesized as a natural form. The absolute configuration of phomapyrone B ( 1 ) was estimated to be the ( R )‐form and that of surugapyrone B ( 3 ) being the ( S )‐form. A series of 2‐pyrone derivatives 17 have been synthesized through the established procedure and their DPPH radical‐scavenging activities have also been evaluated.