Diastereoselective Access to Seven-Membered Benzosultams via Palladium-Catalyzed Ring-Opening [3 + 2]-Annulation

A palladium-catalyzed ring-opening [3 + 2]-annulation of spirovinylcyclopropanyl oxindoles with seven-membered cyclic N-sulfonylimines has been developed. A wide range of seven-membered benzosultams featuring both a quaternary center and axially chiral biaryl scaffolds have been afforded in an average yield of 87% with moderate to excellent diastereoselectivities. The enantioenriched benzosultams were also accessed successfully in good yields with excellent atropoenantioselectivities enabled by the Pd₂(dba)₃/(S,S,S)-SKP ligand. The practical utility of this protocol was further demonstrated by the gram-scale reaction and diversified synthetic transformations of the desired seven-membered benzosultam.