Convergent and Stereospecific Synthesis of Highly Substituted Azepines

This study reported a convergent pattern to stereospecifically synthesize 4,5-dihydrogen azepine from simple and readily available starting materials, addressing synthetic and stereoselective issues. Several synthetically important transformations, such as Simmon-Smith cyclopropanation, halogenation, and hydrogenation, demonstrated the utilities of this strategy. Particularly, the final azepine products could effectively contract into highly substituted pyridine derivatives through an intramolecular oxidation rearrangement.