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Updated: Jun 21, 2026

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Asymmetric [3 + 2] Cycloaddition Employing N, N'-Cyclic Azomethine Imines Catalyzed by Chiral-at-Metal Rhodium
Jun Gong1,2, Qian Wan1, Qiang Kang1
1Key Laboratory of Coal to Ethylene Glycol and Its Related Technology , Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , 155 Yangqiao Road West , Fuzhou 350002 , China.
Abstract:
An efficient asymmetric 1,3-dipolar cycloaddition of α,β-unsaturated 2-acyl imidazoles with N, N'-cyclic azomethine imines catalyzed by a chiral-at-metal rhodium complex is reported. The corresponding N, N'-bicyclic pyrazolidine derivatives with three contiguous tertiary stereocenters were obtained in good yields (up to 99%) with excellent stereoselectivities (>20:1 dr and >99% ee). Remarkably, as little as 0.5 mol % of a chiral Rh(III) complex can promote a gram-scale reaction with excellent yield and enantioselectivity.
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