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Updated: Sep 14, 2025

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Strain Release Cycloadditions of 2H-Azirines: Access to Polycyclic Heterocycles
Kévin Lebair1,2, Kaitlin A Isfeld3, Rebecca L Davis3
1Département de Chimie, Centre for Green Chemistry and Catalysis, Université de Montréal, 1375 Avenue Thérèse-Lavoie-Roux, Montréal, QC H2V 0B3, Canada.
None:
A strain release cycloaddition has been developed that exploits intermediate azirines formed via irradiation with blue LEDs. Subsequent cycloaddition with pyrones afforded novel aza-heterocycles (13 examples, 42%→66% yields). A variety of substituents were tolerated. Computational analysis suggests a kinetically favored endo-[4 + 2]cycloaddition that occurs from the least sterically encumbered face of the azirine. Distortion/interaction analysis suggests that the energetic penalty associated with azirine deformation is the primary factor contributing to the observed selectivity.
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