Ring Opening of Oxiranes with Amines Using Iodolium Salts as XB-Precatalysts
Abstract
Herein, we report the nucleophilic ring-opening of oxiranes with substituted amines using N-heterocycle-substituted iodolium salts (NHISs) as Lewis acid pre-catalysts. Using the ring-opening of styrene oxide by aniline as a model reaction, we demonstrate that NHISs enable efficient β-aminoalcohol formation at room temperature and with pre-catalyst loadings as low as 2.5 mol%. The optimized protocol was successfully applied to a broad range of substituted oxiranes and amines, affording the corresponding β-aminoalcohols in isolated yields of up to 98%. Based on control experiments and recent literature examples, we show that the iodolium salt is not a simple spectator but, under the reaction conditions, undergoes an amine-induced intramolecular aryl–aryl coupling to generate an electron-deficient iodoarene and an ammonium borate salt in situ. On this basis, we propose a dual activation mechanism in which halogen-bond (XB) donor activation of the epoxide operates in concert with an in situ generated β-hydroxyammonium co-catalyst.
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BibTeX
@misc{okashah2026ring,
title = {{Ring Opening of Oxiranes with Amines Using Iodolium Salts as XB-Precatalysts}},
author = {Ibrahim K. Okashah and Mattis Damrath and Jan Rick Koch and Boris J. Nachtsheim},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010577/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010577/v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Ring Opening of Oxiranes with Amines Using Iodolium Salts as XB-Precatalysts
AU - Ibrahim K. Okashah
AU - Mattis Damrath
AU - Jan Rick Koch
AU - Boris J. Nachtsheim
PY - 2026
DA - 2026/10/16
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010577/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010577/v1
AB - Herein, we report the nucleophilic ring-opening of oxiranes with substituted amines using N-heterocycle-substituted iodolium salts (NHISs) as Lewis acid pre-catalysts. Using the ring-opening of styrene oxide by aniline as a model reaction, we demonstrate that NHISs enable efficient β-aminoalcohol formation at room temperature and with pre-catalyst loadings as low as 2.5 mol%. The optimized protocol was successfully applied to a broad range of substituted oxiranes and amines, affording the corresponding β-aminoalcohols in isolated yields of up to 98%. Based on control experiments and recent literature examples, we show that the iodolium salt is not a simple spectator but, under the reaction conditions, undergoes an amine-induced intramolecular aryl–aryl coupling to generate an electron-deficient iodoarene and an ammonium borate salt in situ. On this basis, we propose a dual activation mechanism in which halogen-bond (XB) donor activation of the epoxide operates in concert with an in situ generated β-hydroxyammonium co-catalyst.
ER -