Phosphine-Catalyzed Enantioselective [4 + 3] Annulation of Allenoates with C,N-Cyclic Azomethine Imines: Synthesis of Quinazoline-Based Tricyclic Heterocycles.

With the use of a commercially available chiral phosphine as the catalyst, the first catalytic enantioselective [4 + 3] annulation of allenoates with C,N-cyclic azomethine imines is developed. The reaction works efficiently under mild reaction conditions to afford seven-membered ring-fused quinazoline-based tricyclic heterocycles in high yields with good to excellent diastereo- and enantioselectivities.