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.