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Updated: Jul 26, 2025

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Mild Installation of Piperidines on 4-Alkylpyridines
Jiaqi Shi1, Faizan Rasheed1, Dan Fishlock2
1Department of Chemistry, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada!
Abstract:
We report a mild method for the synthesis of scaffolds bearing 4-pyridine and 4-piperidine moieties joined by a substituted methylene group. The method exploits the latent nucleophilicity of 4-alkylpyridines and the inherent electrophilicity of pyridines. 4-Alkylpyridines are transformed into nucleophilic alkylidene dihydropyridines (ADHPs) through a soft enolization approach using triethyl amine and chloroformate reagents. HCl is used to promote the addition of ADHPs to pyridine, yielding an adduct bearing pyridine and protected dihydropyridine fragments. Transfer hydrogenation delivers the desired compounds in good yields.
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