Total synthesis of neurymenolide A based on a gold-catalyzed synthesis of 4-hydroxy-2-pyrones.

Treat me gently: for a selective synthesis of the unusually sensitive cyclophanic α-pyrone neurymenolide A, the chosen catalysts must be able to distinguish between six different sites of unsaturation, without scrambling any of the skipped π systems. This challenge was met with a new gold-catalyzed pyrone synthesis in combination with a molybdenum-catalyzed ring-closing alkyne metathesis.