Total Synthesis of Natural (+)-Phomopsolide B, an Antifeedant against Elm Bark Beetle

The total synthesis of natural (+)-phomopsolide B (2) is described. A 5,6-dihydro-2H-pyran-2-one framework was constructed by coupling chiral aldehyde 4 and 4-oxygenated enaminoester 5. The resulting 5,6-dihydro-4-pyrrolidyl-2H-pyran-2-one (3) was converted to natural (+)-phomopsolide B (2) in several steps.