How do you draw a glucose chair?

How do you draw a glucose chair?

1 Answer

1. Draw a basic Haworth projection with the ring oxygen at the top.
2. Draw a CH2OH on C-5 .
3. Draw an OH below the ring on C-1 for the α form (draw it above the ring for the β form).
4. Draw all the OH groups on the right side of the Fischer projection on the bottom of the ring.

Which chair conformation of glucose is more stable?

The most stable form of the common sugar glucose contains a six-membered ring in the chair conformation with all the substituents equatorial.

How do you number a chair conformation?

Number the carbons in your cyclohexane and in your chair. Clockwise or counterclockwise doesn’t matter, as long as you use the same direction for both molecules. Then simply compare. Identify the carbon number for the first substituent, if it’s wedged add it to the up position.

What are the conformations of glucose?

Glucose, in its most abundant form in solution, is a six-membered ring adopting a chair conformation with all substituents equatorial. The lower energy chair conformation is the one with three of the five substituents (including the bulky –CH2OH group) in the equatorial position.

What is chair conformation?

Chair conformation: A six-membered ring conformation in which atoms 2, 3, 5, and 6 lie in the same plane, atom 1 lies above the plane, and atom 4 lies below the plane.

Does fructose have a chair conformation?

The chair form of fructose follows a similar pattern as that for glucose with a few exceptions. Since fructose has a ketone functional group, the ring closure occurs at carbon # 2. In the case of fructose a five membered ring is formed.

Is axial or equatorial more stable?

A conformation in which both substituents are equatorial will always be more stable than a conformation with both groups axial.

What is a 1/3 Diaxial interaction?

1,3-Diaxial interactions are steric interactions between an axial substituent located on carbon atom 1 of a cyclohexane ring and the hydrogen atoms (or other substituents) located on carbon atoms 3 and 5.

How to choose the more stable chair conformation of a cyclohexane?

So, choosing the more stable chair conformation is straightforward when there is only one group on the cyclohexane. You just need to find the energy value for the axial group: However, if there are more groups on the cyclohexane, we need to take into consideration the 1,3-diaxial interaction of all.

Is the axial conformer less stable than the equatorial conformer?

In the previous two posts, we have talked about drawing the ring-flip of chair conformations and the A value (1,3-diaxial interactions). And we learned that for a given cyclohexane, the axial conformer is less stable than the corresponding equatorial conformer.

What is the steric strain of a chair conformer?

And now the stabilities: For each chair conformer, add the energy of all the groups on axial position. In the first conformer, we have two chlorines in axial positions, so the total steric strain is: For the second conformer, the chlorines now are equatorial, and we only have one methyl group in axial position.

What is the most stable conformation of Cl?

The most stable conformation is the one where the most bulky group is positioned equatorial. However, do I prioritize Cl over the methyl- and isopropyl-group or are the two groups more prioritized due to them being bonded to Hydrogens which take up more space than a Cl-atom.