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

A palladium-catalyzedring-opening [3 + 2]-annulation of spirovinylcyclopropanyloxindoles with seven-membered cyclic N-sulfonylimineshas been developed. A wide range of seven-membered benzosultams featuringboth a quaternary center and axially chiral biaryl scaffolds havebeen afforded in an average yield of 87% with moderate to excellentdiastereoselectivities. The enantioenriched benzosultams were alsoaccessed successfully in good yields with excellent atropoenantioselectivitiesenabled by the Pd-2(dba)(3)/(S,S,S)-SKP ligand. The practicalutility of this protocol was further demonstrated by the gram-scalereaction and diversified synthetic transformations of the desiredseven-membered benzosultam.

Automated summary

A palladium-catalyzed ring-opening [3 + 2]-annulation reaction was developed for the synthesis of seven-membered benzosultams from spirovinylcyclopropanyloxindoles and cyclic N-sulfonylimines. The reaction yielded a wide range of compounds with both a quaternary center and axially chiral biaryl scaffolds, with an average yield of 87% and moderate to excellent diastereoselectivities. Enantioenriched benzosultams were also successfully synthesized in good yields with excellent atropoenantioselectivities using the Pd-2(dba)(3)/(S,S,S)-SKP ligand. The practical utility of this method was demonstrated through gram-scale reactions and diversified synthetic transformations.