Which of the cyclohexane conformation is more stable? (chair of boat)

What factors cause the observed differences in strain energy between the two conformations of the cyclohexane studied above?

To determine the stability of the chair and boat conformations of cyclohexane, we need to consider the factors that contribute to strain energy in these structures.

The chair conformation of cyclohexane is typically more stable than the boat conformation. This is due to several factors:

1. Steric Strain: In the boat conformation, there is significant steric strain due to the interaction between the hydrogen atoms on neighboring carbons. This strain arises because the hydrogens are forced closer together in the boat conformation, leading to unfavorable repulsive interactions. In the chair conformation, the hydrogens are spaced apart, minimizing this steric strain.

2. Angle Strain: The boat conformation also exhibits angle strain. The boat shape forces the C-C-C bond angles to deviate from the ideal tetrahedral angle of 109.5 degrees, resulting in increased strain. In the chair conformation, the bond angles are closer to the ideal, reducing angle strain.

3. Torsional Strain: Torsional strain arises from the eclipsed interactions between the carbon-hydrogen bonds in the boat conformation. In this conformation, the hydrogen atoms on adjacent carbons are positioned in close proximity, leading to unfavorable overlap of electron clouds. The chair conformation reduces torsional strain by placing the hydrogens in a staggered arrangement, minimizing these unfavorable interactions.

In summary, the chair conformation is more stable than the boat conformation due to reduced steric strain, angle strain, and torsional strain.