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Updated: May 26, 2026

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Executing and rationalizing the synthesis of a difluorinated analogue of a ring-expanded calystegine B2
Sara H Kyne1, Jonathan A L Miles, Jonathan M Percy
1WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, UK.
Abstract:
A difluorinated analogue of a ring-expanded calystegine B(2) and some N-protected species were prepared via microwave-mediated transannular ring-opening of an epoxyketone. The diastereofacial selectivity of the epoxidation reaction, which delivers the key intermediate, and the regioselectivity of the transannular reactions were analyzed by density functional theory (DFT) methods. The epoxidation stereoselectivity arises from simple steric control, whereas the ring-closure reactions are subject to thermodynamic control.
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