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Updated: Oct 11, 2025

Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks MOFs

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Published on: January 17, 2020

Probing Catalyst Function - Electronic Modulation of Chiral Polyborate Anionic Catalysts.

Wynter E G Osminski¹, Zhenjie Lu¹, Wenjun Zhao¹

¹Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States.

The Journal of Organic Chemistry

|December 2, 2021

Summary

This summary is machine-generated.

Chiral boroxinate catalysts, using VAPOL and VANOL ligands, enable rapid screening for asymmetric catalysis. Steric and electronic tuning of the phenol component influences asymmetric induction in catalytic aziridination reactions.

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Area of Science:

Organic Chemistry
Catalysis
Asymmetric Synthesis

Background:

Boroxinate complexes of VAPOL and VANOL offer a chiral anionic platform for asymmetric catalysis.
These platforms feature a chiral polyborate core linking alcohols/phenols and biaryl ligands, assembled in situ.
This allows for rapid assembly of diverse chiral catalysts for activity screening.

Purpose of the Study:

To investigate the impact of steric and electronic properties of the phenol/alcohol component on asymmetric induction.
To elucidate the mechanism of the catalytic asymmetric aziridination reaction mediated by these boroxinate catalysts.

Main Methods:

Systematic variation of the phenol/alcohol component in boroxinate catalysts.
Evaluation of catalyst performance in asymmetric aziridination reactions.
Mechanistic studies including Hammett analysis and computational modeling.

Main Results:

The steric and electronic properties of the phenol/alcohol component significantly affect asymmetric induction.
Hammett studies suggest a mechanism involving hydrogen bonding between substrates and the boroxinate core in the enantiogenic step.
Computational studies support this, showing a correlation between electron-donating ability of the phenol and H-O bond distance.

Conclusions:

The boroxinate platform is versatile for developing chiral catalysts for asymmetric aziridination.
The catalytic mechanism involves substrate hydrogen bonding to the boroxinate core, not Lewis acid activation.
Tuning the electronic properties of the phenol component is crucial for optimizing asymmetric induction.