Stability of Cyclohexane Ediols

Cyclohexane ediol is a compound that contains two hydroxyl groups (-OH) attached to a cyclohexane ring. The stability of the compound depends on the relative positions of the hydroxyl groups on the cyclohexane ring. In this case, we have four isomers to consider: cis-1,2-cyclohexane ediol, trans-1,2-cyclohexane ediol, cis-1,3-cyclohexane ediol, and trans-1,3-cyclohexane ediol.

1. cis-1,2-cyclohexane ediol:
- In this isomer, both hydroxyl groups are on the same side of the cyclohexane ring.
- The hydroxyl groups experience steric hindrance due to their close proximity, which can lead to repulsive interactions.
- The cis-1,2 isomer is less stable than the other isomers due to the steric hindrance between the two hydroxyl groups.

2. trans-1,2-cyclohexane ediol:
- In this isomer, the two hydroxyl groups are on opposite sides of the cyclohexane ring.
- The trans-1,2 isomer is more stable than the cis-1,2 isomer because the hydroxyl groups are further apart and experience less steric hindrance.
- However, there is still some steric hindrance between the hydroxyl groups, which affects the stability of the compound.

3. cis-1,3-cyclohexane ediol:
- In this isomer, the two hydroxyl groups are on the same side of the cyclohexane ring, but they are attached to different carbon atoms.
- The cis-1,3 isomer is more stable than the cis-1,2 isomer because the hydroxyl groups are further apart and experience less steric hindrance.
- The distance between the hydroxyl groups reduces the repulsion between them, increasing the stability of the compound.

4. trans-1,3-cyclohexane ediol:
- In this isomer, the two hydroxyl groups are on opposite sides of the cyclohexane ring and are attached to different carbon atoms.
- The trans-1,3 isomer is the most stable among the four isomers.
- The hydroxyl groups are farthest apart in this isomer, minimizing steric hindrance and repulsive interactions.
- The distance between the hydroxyl groups maximizes the stability of the compound.

Therefore, the most stable compound among the given options is trans-1,3-cyclohexane ediol (option D).