α-Amino Acetal: A Synthetic Intermediate for the Construction of Aza-Polycycles.

One-step construction of aza-polycyclic skeletons was realized through double cyclization of the oxocarbenium and carbocation intermediates generated from α-amino acetals, which were designed and synthesized by employing our α-amination protocol of aldehydes. A simple process, a broad substrate range, commercialized materials, and extensive applications demonstrated the generality and effectiveness of this method.