Stereochemical factors determining the effects of glycosylation on the 13C chemical shifts in carbohydrates
Article first published online: 12 APR 2005
Copyright © 1988 John Wiley & Sons, Ltd.
Magnetic Resonance in Chemistry
Volume 26, Issue 9, pages 735–747, September 1988
How to Cite
Shashkov, A. S., Lipkind, G. M., Knirel, Y. A. and Kochetkov, N. K. (1988), Stereochemical factors determining the effects of glycosylation on the 13C chemical shifts in carbohydrates. Magn. Reson. Chem., 26: 735–747. doi: 10.1002/mrc.1260260904
- Issue published online: 12 APR 2005
- Article first published online: 12 APR 2005
- Manuscript Revised: 26 APR 1988
- Manuscript Accepted: 26 APR 1988
- Manuscript Received: 9 FEB 1988
- 13C NMR;
- Proton-proton interaction;
Basic stereochemical factors have been revealed which affect the 13C chemical shifts in glycosides with a chiral cyclohexane-type aglycone and in disaccharides with a pyranosidic aglycone. The effects of glycosylation depend on the configuration of the anomeric centre of the glycosylating sugar residue (glycone) and on the relative absolute configuration of the glycone and aglycone. When at least one of the carbons of the aglycone, adjacent to the glycosylated carbon, bears an equatorial proton, this dependence is well accounted for by a strengthening or weakening of the spatial interaction between the protons of the glycone and aglycone, caused by a change in the conformation around the glycosidic linkage. Regularities in the glycosylation effects for disaccharides are generalized for various modes of substitution and different general configurations of the pyranosidic aglycones. Simple rules have been formulated for the prediction of the magnitudes of the glycosylation effects which can be used for the determination of some unknown structural elements in glycosides and disaccharides, in particular the absolute configuration of one of the constituent sugars.