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Updated: May 16, 2026

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Group 11 metal amide-catalyzed asymmetric cycloaddition reactions of azomethine imines with terminal alkynes
Takaki Imaizumi1, Yasuhiro Yamashita, Shū Kobayashi
1Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Abstract:
We developed a 1,3-dipolar cycloaddition reaction of azomethine imines with terminal alkynes catalyzed by group 11 metal amides to provide N,N-bicyclic pyrazolidinone derivatives. This reaction afforded the cycloadducts in a unique 5,7-disubstituted manner. Furthermore, we succeeded in applying this catalysis to asymmetric reactions, and the desired heterocycles were produced in high yields with exclusive regioselectivity and high enantioselectivity. Mechanistic studies elucidated a stepwise reaction pathway and critical features that determine the regioselectivity.
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