Diastereoselective construction of cage-like and bridged azaheterocycles through dearomative maximization of the reactive sites of azaarenes

A highly diastereoselective multicomponent dearomative multifunctionalization of N-alkyl activated azaarenes with 1,5-diazapentadienium salts has been developed, which not only represented a significant advance in maximum utilization of the reactive sites of azaarenes, but also provided a convenient and robust approach to access structurally rigid and synthetically challenging cage-like and bridged azaheterocycles. As an important complement, we also realized the dearomative multi-functionalization of N-aryl azaarenes through an in situ activation strategy. Moreover, the workup-directed selective tri- and bi-functionalization of isoquinolinium salts have been accomplished.