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Updated: Aug 19, 2025
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Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
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Distance-Triggered Distinct Aryl Migrations on Azidodiboranes
Tong-Tong Liu1, Jiaxin Chen2, Bing-Tao Guan1
1Department of Chemistry, Fudan University, Shanghai, 200438, P. R. China.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|November 29, 2022
Summary
The boron-boron separation distance in azidodiboranes dictates aryl migration pathways. Shorter distances promote heterolateral migration, while longer distances lead to bis-azidoboranes and subsequent cyclization reactions.
Area of Science:
- Organoboron chemistry
- Synthetic inorganic chemistry
- Reaction mechanism studies
Background:
- Azidodiboranes are precursors to novel heterocyclic compounds.
- Aryl migration reactions in boron compounds are sensitive to structural parameters.
- Understanding reaction pathways is crucial for designing new synthetic methodologies.
Purpose of the Study:
- To investigate the influence of boron-boron separation distance on aryl migration in azidodiboranes.
- To synthesize and characterize novel boron-containing heterocycles.
- To elucidate the mechanisms of aryl migration and subsequent reactions.
Main Methods:
- Synthesis of biphenylene and xanthrene based azidodiboranes.
- Analysis of reaction products using spectroscopic techniques.
- Density functional theory (DFT) calculations to model reaction pathways.
Main Results:
- Distinct aryl migration pathways observed based on boron-boron distance.
- Formation of a seven-membered azadiborepin via heterolateral migration.
- Isolation of a stable bis-azidoborane scaffold from longer-distance precursors.
- Synthesis of an eight-membered oxazadiborocine through homolateral migration and cycloaddition.
Conclusions:
- Boron-boron separation distance is the key determinant of aryl migration modes in azidodiboranes.
- DFT calculations confirm the role of boron-boron distance in dictating reaction outcomes.
- The study provides insights into the synthesis of diverse boron heterocycles.
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