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Updated: Mar 26, 2026

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Lewis Acid Catalyzed [4 + 3] Cycloaddition of Propargylic Alcohols with Azides
Ya-Ping Han1, Xian-Rong Song2, Yi-Feng Qiu1
1State Key Laboratory of Applied Organic Chemistry, Lanzhou University , Lanzhou 730000, China.
Abstract:
An unprecedented Lewis acid catalyzed [4 + 3] cycloaddition reaction is described that provides a straightforward route to polycyclic products containing an imine-based indole azepine scaffold, starting from readily available internal tertiary alkynols and azides. This cycloaddition protocol provides efficient and atom-economical access to a new class of fascinating imine-containing products in satisfactory yields, which has shown good application in the construction of seven-membered N-heterocycles.
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