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Hierarchical and Programmable One-Pot Oligosaccharide Synthesis
Published on: September 6, 2019
Conformational domino effect in saccharides. 2. Anomeric configuration control
Alfredo Roën1, Carlos Mayato, Juan I Padrón
1Instituto Universitario de Bio-Orgánica Antonio González, Departamento de Química Orgánica, Universidad de La Laguna, 38206 La Laguna, Tenerife, Spain.
The Journal of Organic Chemistry
|August 30, 2008
Summary
Researchers synthesized alpha-anomer diglucopyranosides and found their hydroxymethyl group rotation depends on steric effects, not Taft parameters. This confirms a conformational domino effect influenced by anomeric configuration.
Area of Science:
- Carbohydrate Chemistry
- Organic Chemistry
- Structural Biology
Background:
- Understanding the conformational flexibility of oligosaccharides is crucial for elucidating their biological roles.
- Alkyl diglucopyranosides serve as valuable model compounds for studying glycosidic linkage dynamics.
Purpose of the Study:
- To synthesize and characterize a series of alkyl alpha-D-glucopyranosyl-(1-->6)-alpha-D-glucopyranosides.
- To investigate the influence of aglycon structure and solvent on the conformational properties of these alpha-anomers.
- To explore the relationship between steric parameters and rotational populations.
Main Methods:
- Nuclear Magnetic Resonance (NMR) spectroscopy for structural and dynamic analysis.
- Circular Dichroism (CD) spectroscopy for conformational studies.
- Synthesis of alkyl alpha-D-glucopyranosyl-(1-->6)-alpha-D-glucopyranosides.
Main Results:
- Rotational populations of the hydroxymethyl group (omega) are dependent on the aglycon and solvent, primarily due to steric effects in the alpha-anomer series.
- A correlation was observed between rotational populations and molar refractivity (MR) steric parameters, unlike the beta-anomer series which correlated with Taft's parameters.
- The conformational domino effect, previously predicted for beta-anomers, is supported by the alpha-anomer series, with anomeric configuration being a key controlling factor.
Conclusions:
- The anomeric configuration significantly influences the conformational domino effect in alkyl diglucopyranosides.
- Steric effects, quantified by molar refractivity, play a dominant role in controlling hydroxymethyl group rotation in alpha-anomers.
- These findings provide deeper insights into the structure-property relationships of oligosaccharides.
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