Rapid Synthesis of Fused Oxabicycles through the Molecular Rearrangement of Spirocyclic Ethers

A molecular rearrangement of 5,5-spirocyclic cyclopentenones to 5,6-fused cyclopentenones catalyzed by Amberlyst((R))15 is described. This work emphasizes the utility of renewable resources, such as furfural, that can be transformed into a variety of valuable products. It also highlights the viability of 5,5-spirocycles as intermediates en route to 5,6-fused cyclopentenones.