Enantioselective and collective syntheses of xanthanolides involving a controllable dyotropic rearrangement of cis-ß-lactones.

Let's swap: a scalable, atom-economic, enantio-, and diastereoselective synthetic route to trisubstituted γ-butyrolactones based on a Wagner-Meerwein-type dyotropic rearrangement of cis-ß-lactones is described. This methodology was applied in efficient and protecting-group-free formal syntheses and total syntheses of various xanthanolide natural products.