An unprecedented strain‐driven dyotropic rearrangement of α‐methylene‐β‐lactones has been realized, which enables the efficient access of a wide range of α‐methylene‐γ‐butyrolactones displaying remarkable structural diversity. Several appealing features of the reaction, including excellent efficiency, high stereospecificity, predictable chemoselectivity and broad substrate scope, render it a powerful tool for the synthesis of MBL‐containing molecules of either natural or synthetic origin. Both experimental and computational evidences suggest that the new variant of dyotropic rearrangements proceed in a dualistic pattern: while an asynchronous concerted mechanism most likely accounts for the reactions featuring hydrogen migration, a stepwise process involving a phenonium ion intermediate is favored in the cases of aryl migration. The great synthetic potential of the title reaction is exemplified by its application to the efficient construction of several natural products and relevant scaffolds.

Asymmetric total syntheses of insulicolide A, 14- O-acetylinsulicolide A, 6β,9α-dihydroxy-14- p-nitrobenzoyl cinnamolide, and 7α,14-dihydroxy-6β- p-nitrobenzoylconfertifolin have been achieved for the first time. The key steps in the synthesis include: (1) an iridium-catalyzed enantioselective polyene cyclization to construct the drimane core bearing two all-carbon quaternary chiral centers at C4 and C10 and (2) a cascade ozonolysis of the phenol ring to form the lactone fragment of the target molecules.