Novel Skeleton Transformation Reaction of α‑Pyrone Derivatives to Spirobicyclo[3.1.0]hexane Derivatives Using Dimethylsulfoxonium Methylide

By applying a skeleton transformation reaction using dimethylsulfoxonium methylide, a novel reaction was identified by which 5,6,7,8-tetrahydrocoumarin with the electron-withdrawing group at C3 was led to the spirobicyclo[3.1.0]hexane-cyclohexane derivative. Moreover, by establishing the scope of this reaction, it was confirmed that it is possible to apply this reaction to not only ring-fused α-pyrone derivatives but also alkyl-chain-substituted α-pyrone derivatives in moderate to good yields.