DMAP‐promoted [4 + 2]/[3 + 3] Annulation Cascade Reaction of Morita–Baylis–Hillman Carbonates with Conjugated Imines to Access Functionalized Benzo[c][2,7]naphthyridine Skeletons

A novel, synthetically straightforward, selective DMAP‐promoted [4 + 2]/[3 + 3] annulation domino reaction of o‐acylamino‐aryl Morita−Baylis−Hillman (MBH) carbonates with α,β‐unsaturated imines to construct complex fused [2,7]naphthyridine frameworks has been developed. The reaction provides a step‐economic strategy for the direct synthesis of functionalized benzo[c][2,7]naphthyridines containing three stereogenic centers in high yields with excellent chemo‐, regio‐, and diastereoselectivity under mild reaction conditions. More importantly, this transformation enables the simultaneous formation of four new bonds and two new six‐membered N‐heterocycles in only one step. Additionally, the synthetic utility of this method has been demonstrated through its application in the late‐stage modification of pharmaceutically active molecules.