Determination of relative stereochemistry
From NMR Wiki
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pages={870--871}, | pages={870--871}, | ||
year={1999} | year={1999} | ||
| + | } | ||
| + | </bibtex> | ||
| + | <hr> | ||
| + | The following article shows how the relative stereochemistry of 1,3-diols may be determined as ''syn-'' or ''anti-'' by analyzing the carbon shifts after functionalizing the 1,3-diols to acetonides. If the 1,3-diols have a ''syn-'' orientation to one another, the acetonide will have a chair conformation and the methyl carbons of the acetonide will have different shifts due to one being axial, the other being equitorial. If the diols are ''anti-'', then the acetonide will exist as a twist boat conformation and the methyl carbons will have similar carbon shifts. | ||
| + | |||
| + | <bibtex> | ||
| + | @article{rychnovsky1993atc, | ||
| + | title={{Analysis of two carbon-13 NMR correlations for determining the stereochemistry of 1, 3-diol acetonides}}, | ||
| + | author={Rychnovsky, S.D. and Rogers, B. and Yang, G.}, | ||
| + | journal={The Journal of Organic Chemistry}, | ||
| + | volume={58}, | ||
| + | number={13}, | ||
| + | pages={3511--3515}, | ||
| + | year={1993}, | ||
| + | publisher={American Chemical Society} | ||
} | } | ||
</bibtex> | </bibtex> | ||
[[Category:Small Molecule NMR]] [[Category:Scalar Coupling]] [[Category:NMR Bibliography]] | [[Category:Small Molecule NMR]] [[Category:Scalar Coupling]] [[Category:NMR Bibliography]] | ||
Revision as of 19:38, 15 February 2008
This review article discusses use of 2,3JCH, 3JHH scalar couplings and 13C chemical shifts for assignment of relative stereochemistry of centers (marked in bold) in -CHX-CHY- and -CHX-CH2-CHY- hydrocarbon fragments, where X and Y are polar substituents.
2JCH couplings are useful in fragments CYH-CHX where substituent X is polar (and the coupling between atoms marked in bold is observed).
Bifulco, G., Dambruoso, P., Gomez-Paloma, L., Riccio, R.. Determination of Relative Configuration in Organic Compounds by NMR Spectroscopy and Computational Methods
Riccio, R., Bifulco, G., Cimino, P., Bassarello, C., Gomez-Paloma, L.. {Stereochemical analysis of natural products. Approaches relying on the combination of NMR spectroscopy and computational methods}
- Pure and Applied Chemistry 75(2-3):295--308, 2003
- BibTeX
Marquez, B.L., Gerwick, W.H., Williamson, R.T.. {Survey of NMR experiments for the determination of n J (C, H) heteronuclear coupling constants in small molecules}
- Magn. Reson. Chem 39:499--530, 2001
- BibTeX
The article below is the pioneering work showing that 2,3JCH and 3JHH coupling constants can be used to determine relative stereochemistry of two adjacent stereocenters in acyclic hydrocarbons. The analysis is based on the assumption (supported by molecular mechanics calculations) that most acyclic hydrocarbons substituted with -OH, -OCH3, -CH3 and other non-bulky substituents favor gauche or anti conformations within 10o accuracy. Also authors state that this J-based method to determine relative stereochemistry works for the cases where one rotamer is at least 85% populated.
Matsumori, N., Kaneno, D., Murata, M., Nakamura, H., Tachibana, K.. Stereochemical determination of acyclic structures based on carbon-proton spin-coupling constants. A method of configuration analysis for natural products
Ciminiello, P., Dell'Aversano, C., Fattorusso, E., Forino, M., Magno, S., Di Rosa, M., Ianaro, A., Poletti, R.. {Structure and Stereochemistry of a New Cytotoxic Polychlorinated Sulfolipid from Adriatic Shellfish}
Murata, M., Matsuoka, S., Matsumori, N., Paul, GK, Tachibana, K.. {Absolute configuration of amphidinol 3, the first complete structure determination from amphidinol homologues: application of a new configuration analysis based on carbon-hydrogen spin-coupling constants}
- J Am Chem Soc 121:870--871, 1999
- BibTeX
The following article shows how the relative stereochemistry of 1,3-diols may be determined as syn- or anti- by analyzing the carbon shifts after functionalizing the 1,3-diols to acetonides. If the 1,3-diols have a syn- orientation to one another, the acetonide will have a chair conformation and the methyl carbons of the acetonide will have different shifts due to one being axial, the other being equitorial. If the diols are anti-, then the acetonide will exist as a twist boat conformation and the methyl carbons will have similar carbon shifts.
Rychnovsky, S.D., Rogers, B., Yang, G.. {Analysis of two carbon-13 NMR correlations for determining the stereochemistry of 1, 3-diol acetonides}
- The Journal of Organic Chemistry 58(13):3511--3515, 1993
- BibTeX
