Syntheses of Novel Spirobenzazepinoindole Derivatives via Lewis‐Acid Catalyzed Pictet‐Spengler Cyclization

The syntheses of novel spirobenzazepinoindole derivatives has been achieved through a highly efficient and synthetic route. The approach involves a two-step reaction, utilizing indole derivatives, 2-amino benzyl alcohol, and ninhydrin as key starting materials under mild reaction conditions. The reaction proceeds via a sequential cascade process involving cyclization, condensation and spiro-annulation, leading to the formation of the spirobenzazepinoindole core structure in good to excellent yields. The method offers broad substrate scope, high atom economy, and operational simplicity. The synthesized spirobenzazepinoindoles were fully characterized by spectroscopic techniques, including NMR (¹H & ¹³C), IR and mass spectrometry. The methodology provides a valuable tool for the rapid generation of structurally complex spirobenzazepinoindoles, which could serve as scaffolds for the development of new therapeutic agents.