Issue 24, 2020

Direct regioisomer analysis of crude reaction mixtures via molecular rotational resonance (MRR) spectroscopy

Abstract

Direct analyses of crude reaction mixtures have been carried out using molecular rotational resonance (MRR) spectroscopy. Two examples are presented, a demonstration application in photocatalytic CH-arylation as well as generation of an intermediate in a natural product synthesis. In both cases, the reaction can proceed at more than one site, leading to a mixture of regioisomers that can be challenging to distinguish. MRR structural parameters were calculated for the low lying conformers for the desired compounds, and then compared to the experimental spectra of the crude mixtures to confirm the presence of these species. Next, quantitation was performed by comparing experimentally measured line intensities with simulations based on computed values for the magnitude and direction of the molecular dipole moment of each species. This identification and quantification was performed without sample purification and without isolated standards of the compounds of interest. The values obtained for MRR quantitation were in good agreement with the chromatographic values. Finally, previously unknown impurities were discovered within the photocatalytic CH-arylation work. This paper demonstrates the utility of MRR as a reaction characterization tool to simplify analytical workflows.

Graphical abstract: Direct regioisomer analysis of crude reaction mixtures via molecular rotational resonance (MRR) spectroscopy

Supplementary files

Article information

Article type
Edge Article
Submitted
31 3 2020
Accepted
30 5 2020
First published
08 6 2020
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2020,11, 6332-6338

Direct regioisomer analysis of crude reaction mixtures via molecular rotational resonance (MRR) spectroscopy

L. A. Joyce, Danielle M. Schultz, E. C. Sherer, J. L. Neill, R. E. Sonstrom and B. H. Pate, Chem. Sci., 2020, 11, 6332 DOI: 10.1039/D0SC01853H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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