“Enantiodifferentiation through Frequency-Selective Pure-Shift 1H Nuclear Magnetic Resonance Spectroscopy” by Laura Castañar, Míriam Pérez-Trujillo, Pau Nolis, Eva Monteagudo, Albert Virgili and Teodor Parella. ChemPhysChem,15 (2014) 854-857.
A frequency-selective 1D 1H NMR experiment for the fast and sensitive determination of chemical shift differences between overlapped resonances is proposed. The resulting fully homodecoupled 1H resonances appear as resolved 1D singlets without their typical JHH multiplet structure. The achieved high signal dispersion is here exploited in enantiodiscrimination studies using chiral solvating agents. We have demonstrated that the homodecoupled SPFGE method is a robust and sensitive analytical NMR spectroscopy tool for the fast and simple discrimination of chemical-shift differences in overlapped signals and for the determination of the ee in the presence of CSAs. Its major advantage lies in the single-scan and 1D acquisition modes, as the resulting simplified singlet signals facilitate a better analysis. It has been shown that homodecoupled signals can also be retrieved for resonances obscured by other more intense signals or in overcrowded regions by using a preparatory TOCSY editing.
Reference:
“Full sensitivity and enhanced resolution in homodecoupled band-selective NMR experiments” by L. Castañar, P. Nolis, A. Virgili and T. Parella. Chem. Eur. J. 2013, 19, 17283-17286. DOI:10.1002/chem.201303235
