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Updated: Jul 5, 2026

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Catalytic aza-Wittig cyclizations for heteroaromatic synthesis
Stephen P Marsden1, Alison E McGonagle, Ben McKeever-Abbas
1School of Chemistry, University of Leeds, Leeds, UK. s.p.marsden@leeds.ac.uk
Abstract:
The first examples of heterocycle synthesis by iminophosphorane formation/intramolecular aza-Wittig cyclizations that are catalytic in the organophosphorus component are reported. The reaction has been demonstrated in the synthesis of both azine (phenanthridine) and azole (benzoxazole) heterocycles. Catalyst loadings down to 1 mol % have been used with little or no loss in reaction efficiency. The intimate involvement of the phosphine oxide in the catalytic cycle has been verified by in situ infrared spectroscopy.
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