Silver-Mediated Dual Oxidation of 1,3-Dicarbonyls for Migration–Annulation

A new type of radical cascade reaction has been reported, by which free radicals were generated twice successively through the implementation of dual oxidation on a 1,3-dicarbonyl compound in a single operation, thereby realizing a conceptually novel alkynyl migration-annulation mode. The reaction involved addition, 1,2-alkynyl migration, and 4-exo-dig/6-endo-trig bicyclization under mild reaction conditions, offering an efficient route to tetrahydrocyclobuta[b]naphthalene in good yields. Control experiments revealed migration products as key intermediates and elucidated the step sequence in these transformations.