Long-range shielding effects in the (1)H NMR spectra of Mosher-like ester derivatives

Long-range shielding effects in the (1)H NMR spectra of Mosher-like ester derivatives

The relative magnitudes of the chemical shift differences (Deltadeltas) in the two diastereomers of menthyl esters of known chiral derivatizing agents (CDAs) were compared to those of the alpha-methoxy-alpha-trifluoromethyl-1-naphthylacetyl (MTN((1))A) analogues I. Discrimination of the terminal dia...

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Bibliographic Details
Published in:Organic letters 2010-04, Vol.12 (8), p.1768-1771
Main Authors: Hoye, Thomas R, Erickson, Sara E, Erickson-Birkedahl, Sherrie L, Hale, Christopher R H, Izgu, Enver Cagri, Mayer, Michael J, Notz, Patrick K, Renner, Matthew K
Format: Article
Language:eng
Subjects:
Esters - chemistry
Magnetic Resonance Spectroscopy
Naphthols - chemistry
Phenylacetates - chemistry
Stereoisomerism
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Summary:The relative magnitudes of the chemical shift differences (Deltadeltas) in the two diastereomers of menthyl esters of known chiral derivatizing agents (CDAs) were compared to those of the alpha-methoxy-alpha-trifluoromethyl-1-naphthylacetyl (MTN((1))A) analogues I. Discrimination of the terminal diastereotopic methyl resonances in esters of the homologous, symmetrical carbinols II was evaluated. Remarkably, the methyls differed in the MTN((1))A esters III even when n = 15; an unexpected crossover in the sign of the Deltadelta values was also observed.
ISSN:1523-7052