Representing Chiral cyclohexane on a chair conformation

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In summary, the conversation is about converting a compound's structure into a chair conformation for an organic chemistry assignment. The question is whether equatorial substituents are always represented as wedges on a structural diagram or not, and if not, how to approach this question. The response is that the use of wedges and dashes in structural diagrams is unrelated to chair/boat or axial/equatorial placements, and building a model may be helpful in visualizing the structure.
  • #1
grewas8
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For an assignment for organic chem the question asks to convert the structure of a compound into a chair conformation
my question is that are equatorial substituents always the ones that are represented as a wedge on a structural diagram?
If not could someone please give me tips on how to approach this question?
thanks
P.S. the diagram of the molecule is attached and thick black line represents wedge, thin red line represents dash
 

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  • #2
Bonds that are depicted as wedges are drawn to indicate that the bond is pointed toward the observer. Dashed ones are pointed away from the observer. They are entirely unrelated to chair/boat or axial/equatorial placements per se. If I had little experience visualizing structures in 3D I would approach this problem by building a model. It is very difficult to explain the structure without them. It can be done, but it is difficult.
 
  • #3
Great question! In a chair conformation, the equatorial substituents are typically represented as wedges on a structural diagram. However, this is not always the case. It is important to remember that the orientation of wedges and dashes on a structural diagram is relative and can be changed without affecting the overall structure of the molecule.

To approach this question, you can follow these steps:

1. Identify the chiral center(s) in the molecule: In this case, the chiral center is the carbon atom with four different substituents attached to it.

2. Draw the chair conformation: Start by drawing the chair conformation of the molecule, with the chiral center in the center of the ring. Remember that the equatorial positions will be pointing outwards, while the axial positions will be pointing upwards and downwards.

3. Place the substituents on the chair conformation: The substituents can be placed in the equatorial or axial positions. However, as mentioned earlier, the orientation of wedges and dashes is relative, so you can choose to represent the substituents as wedges or dashes as long as the overall structure of the molecule remains the same.

4. Follow the Cahn-Ingold-Prelog (CIP) rules: The CIP rules are used to assign priorities to the substituents attached to a chiral center. The substituents with higher atomic numbers are given higher priority. This will help you determine the correct orientation of the wedges and dashes on the structural diagram.

5. Double-check your structure: Once you have placed all the substituents on the chair conformation, double-check to make sure that the substituents with higher priority are represented as wedges, while the substituents with lower priority are represented as dashes.

Remember, the key is to maintain the correct orientation of the substituents in relation to the chiral center and to follow the CIP rules. I hope this helps! Good luck with your assignment.
 

1. What is a chiral cyclohexane?

A chiral cyclohexane is a type of cyclohexane molecule with four different substituents attached to the six carbon atoms in the ring. This results in the molecule having a non-superimposable mirror image, making it optically active.

2. How do you represent a chiral cyclohexane on a chair conformation?

To represent a chiral cyclohexane on a chair conformation, you need to draw a hexagon with alternating up and down positions. The substituents attached to the carbon atoms on the top of the ring should be drawn pointing upwards, while the substituents on the bottom of the ring should be drawn pointing downwards.

3. Why is it important to represent a chiral cyclohexane on a chair conformation?

Representing a chiral cyclohexane on a chair conformation allows us to visualize the spatial arrangement of the substituents and determine the molecule's chirality. It also helps us understand the molecule's stability and reactivity.

4. What is the difference between an axial and equatorial position on a chair conformation?

An axial position on a chair conformation is when a substituent is pointing straight up or down, perpendicular to the ring. An equatorial position is when a substituent is pointing outwards, parallel to the ring. Axial positions are less stable than equatorial positions due to steric hindrance.

5. Can a chiral cyclohexane have more than one stereoisomer on a chair conformation?

Yes, a chiral cyclohexane can have multiple stereoisomers on a chair conformation. This is because the substituents can be arranged in different positions, resulting in different spatial arrangements and therefore different stereoisomers.

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