<i>N</i>‑Heterocyclic Carbene-Catalyzed\n[3 + 3] Annulation of Enals with Aminonaphthoquinones for the Synthesis\nof Functionalized Aza-anthraquinones

Rapid construction of functionalized aza-anthraquinones\nhas been\nsuccessfully developed via NHC-catalyzed formal [3 + 3] annulation\nof 2-aminoquinones with enals. This reaction features several advantages,\nsuch as readily available starting materials, mild reaction conditions,\nand flexible product transformations. The study on the atroposelective\nversion of this strategy was also carried out, and several C–N\naxial chiral aza-anthraquinones were synthesized in moderate yields\nwith moderate to good enantioselectivities.