A Practical and Metal-Free Approach Towards Synthesis of Spiro-Benzazepinoindole Derivatives via Pentafluorophenol Catalyzed Pictet-Spengler Reaction.

The efficient pentaflurophenol-catalyzed Pictet-Spengler cyclization was carried out which led to the formation of spirobenzazepinoindole. This article examines the methods and modifications of Pictet-Spengler cyclization in the synthesis of intricate organic compounds, emphasizing its significance in drug discovery and development. This reaction generally entails the condensation of an amine with an aldehyde or ketone, succeeded by an intramolecular cyclization step catalyzed by pentafluorophenol, an alternate for metal-mediated catalysts due to its facile characteristics which render it an invaluable asset in organic synthesis and catalysis.

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.