atom‐economic, enantio‐, and diastereoselective synthetic route to trisubstituted γ‐butyrolactones based on a Wagner–Meerwein‐type dyotropicrearrangement of cis‐β‐lactones is described (see scheme). This methodology was applied in efficient and protecting‐group‐free formal syntheses and total syntheses of various xanthanolide natural products.