Diversity-Oriented Synthesis of Diazabicyclo[3.2.1]octanes and Dihydroquinolines via Phosphine-Catalyzed Domino Reactions of o -Amino Arylaldimines with Allenoates

Herein, we disclose a straightforward and diversity-oriented synthetic strategy for the efficient construction of structurally diverse diazabicyclo[3.2.1]octanes and dihydroquinolines. The diazabicyclic products were generated through Lu's [3 + 2] annulation cascaded with an unexpected intramolecular aza-Michael addition. The resulting bridged [3.2.1]bicyclic compounds then served as precursors to dihydroquinolines via three distinct pathways. In addition, control experiments were performed to elucidate the plausible reaction mechanisms underlying the divergent transformations.