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Updated: Feb 28, 2026

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Synthesis of functionalised azepanes and piperidines from bicyclic halogenated aminocyclopropane derivatives
Cheng Chen1, Pullaiah Kattanguru1, Olesya A Tomashenko2
1Laboratoire de Synthèse Organique (LSO), UMR 7652 CNRS/ENSTA/École Polytechnique, Université Paris-Saclay, 91128 Palaiseau Cedex, France. yvan.six@polytechnique.edu.
Abstract:
A series of 6,6-dihalo-2-azabicyclo[3.1.0]hexane and 7,7-dihalo-2-azabicyclo[4.1.0]heptane compounds were prepared by the reaction of dihalocarbene species with N-Boc-2,3-dihydro-1H-pyrroles or -1,2,3,4-tetrahydropyridines. Monochloro substrates were synthesised as well, using a chlorine-to-lithium exchange reaction. The behaviour of several aldehydes and ketones under reductive amination conditions with deprotected halogenated secondary cyclopropylamines was investigated, showing that this transformation typically triggers cyclopropane ring cleavage to give access to interesting nitrogen-containing ring-expanded products.
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