Furo[3,4-b]benzodioxin 1 was found to undergo a doubleDiels–Alder reaction with several dienophiles. The diene reacts directly with the suitable dienophile to give the mono-adduct intermediate that unexpectedly leads to a second cycloaddition at the internal, electron-rich, oxabicyclic C4a–C10a double bond. The resulting bis-adducts were formed under relatively mild conditions with dienophiles ranging