Silver(I)-Catalyzed Enantioselective [3+2]-Cycloaddition Reaction of [alpha]-Silylimines: A Facile Route to Quaternary-Carbon-Rich Scaffolds

A silver-catalyzed highly enantioselective 1,3-dipolar cycloaddition reaction of [alpha]-silylimines with pyrone-based trisubstituted olefins was developed affording bi- and tricyclic [alpha]-quaternary-carbon-rich pyrano-pyrrolidines in excellent yields. The tricyclic benzopyrone adducts thus obtained were efficiently transformed into highly complex tetracyclic scaffolds supporting four consecutive stereogenic centers with three quaternary carbons.