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

A silver-catalyzed highly enantioselective 1,3-dipolar cycloaddition reaction of α-silylimines with pyrone-based trisubstituted olefins was developed affording bi- and tricyclic α-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.