Fischer Projection to Haworth/Chair Conformation

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In summary, in the Haworth projection and chair conformation, it is possible to determine if a ring is beta or alpha by looking at the Fischer projection. However, this can only be done if the Fischer projection is provided beforehand. In aqueous solution, glucose exists in both the open and closed forms in equilibrium. This process of conversion is known as mutarotation, where the C-1→ C-2 bond rotates, producing the alpha and beta anomers. In the case of glucose, beta anomer is more predominant than alpha anomer. This may not be the case for all monosaccharides.
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ngu9997
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Can you tell if the ring will be beta or alpha in the haworth projection, chair conformation by just looking at the Fischer projection, or must you be told first before creating the two from the Fischer? If so, could someone explain how? I've seen a bunch of websites and they all seem to say that you won't be able to tell from a Fischer alone.
 
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In aqueous solution, glucose exists in both the open and closed forms. These two forms always exist in equilibrium. In the process of converting from closed to open form and then back to closed form, the C-1→ C-2 bond rotates. This rotation produces either of the two anomers. We term this phenomenon of opening of the ring, rotation of the C-1→ C-2 bond and the subsequent closing of the ring as mutarotation. So as a result of mutarotation, both the α and β anomers are present in equilibrium in solution. In the case of glucose, β anomer is more predominant than α anomer. This may not be the case with all the monosaccharides.
45281b9f88c4a2720d9de93fae888df32698edb5.png

https://www.khanacademy.org/test-pr...d-ketones/a/cyclic-hemiacetals-and-hemiketals
 

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1. How do you convert a Fischer Projection to a Haworth or Chair Conformation?

The conversion from a Fischer Projection to a Haworth or Chair Conformation involves rotating the molecule 90 degrees and then folding the molecule along the longest chain to form a ring. The horizontal lines in the Fischer Projection become bonds pointing down in the Haworth or Chair Conformation, while the vertical lines become bonds pointing up.

2. What are the advantages of using a Haworth or Chair Conformation over a Fischer Projection?

A Haworth or Chair Conformation provides a more accurate representation of the three-dimensional structure of a molecule, particularly for cyclic molecules. It also allows for easier visualization of the stereochemistry and potential interactions with other molecules.

3. Can a Fischer Projection and a Haworth or Chair Conformation represent the same molecule?

Yes, a Fischer Projection and a Haworth or Chair Conformation can represent the same molecule. They are just different ways of depicting the same molecule in different orientations.

4. How does the numbering of carbon atoms differ between a Fischer Projection and a Haworth or Chair Conformation?

In a Fischer Projection, the carbon atoms are numbered based on their position in the longest chain, with the carbon closest to the functional group being assigned the lowest number. In a Haworth or Chair Conformation, the carbon atoms are numbered clockwise starting from the oxygen atom.

5. Are there any limitations to using a Haworth or Chair Conformation?

One limitation of using a Haworth or Chair Conformation is that it may not accurately depict the actual conformation of a molecule in solution. This is because the Haworth or Chair Conformation is a static representation and does not account for the flexibility and dynamic nature of molecules in solution. Additionally, the Haworth or Chair Conformation is primarily used for cyclic molecules and may not be suitable for representing linear molecules.

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