Synthesis of Intricate Fused N-Heterocycles via Ring-Rearrangement Metathesis

Herein, a facile synthesis of intricate fused N-heterocycles is disclosed by employing CH activation and ring-rearrangement metathesis/enyne ring-rearrangement metathesis as key steps. Interestingly, some of these N-heterocyclic products possess the tricyclic core of epimeloscine, deoxycalyciphylline B, daphlongamine H, isodaphlongamine H, and a bioactive alkaloid, annotinolide A, which shows antiaggregation activity against amyloid-beta (A beta)(1-42) peptide aggregation. Moreover, various starting materials required in this protocol are easily assembled via CX bond annulation of 2-bromo-N-protected aniline with norbornadiene or directing group-assisted ruthenium-catalyzed CH activation of N-methoxybenzamide.