Synthesis of Nitrogen-Containing Heterocycles via Ring-Closing Ene-Ene and Ene-Yne Metathesis Reactions: An Easy Access to 1-and 2-Benzazepine Scaffolds and Five- and Six-Membered Lactams
Résumé
Novel regioselective ring closing ene-yne metathesis provided an efficient access to different substituted 1-benzazepine scaffolds. The reported synthetic approach could also be used as a powerful tool for the selective formation of a highly functionalizable 2-benzazepine core. This synthetic protocol was even proved to be an efficient way to obtain a functionalizable benzazocine derivative. By modifying the structure of the starting materials, the optimized cyclization finally proved to be a suitable technique to obtain five-and six-membered lactams, enhancing the synthetic application of our method. Five-and six-membered lactams were efficiently prepared by ring-closing metathesis involving the loss of ethylene moiety and affording highly functionalizable compounds showing both electron-withdrawing substituents and electron-donor groups.