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Updated: May 12, 2026

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Asymmetric Catalytic (3 + 2) Cyclization and Sequential Reaction to Construct Dihydrofuran- and Azepine-Based
Qiliang Luo1, Yuqiao Zhou1, Jing Zhang1
1Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China.
Abstract:
The enantioselective formal (3 + 2) cyclization and sequential reaction of 2-malononitrile-substituted oxindoles with benzaldehydes and ortho-aminobenzaldehydes were achieved by chiral N,N'-dioxide/metal complex Lewis acid catalysts. This protocol supplies facile and efficient access to highly functionalized chiral dihydrofuran- and azepine-based spirooxindoles. Based on the control experiments and the deuterium labeling studies, the interconversion of (3 + 2) diastereomeric intermediates under the reaction conditions and reversible 1,5-H transfer step were disclosed.
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