I am dealing with two conformations of cis-1,4-dimethylcyclohexane. One conformation is di-axial, and the other one is di-equatorial. Why does di-axial have higher strain energy. I would make sense if the molecule was 1,3-dimethylcyclohexane because then it would the steric hinderance that would cause higher energy. Is it similar with 1,4-.. conformation? If its not steric repulsion, what factors cause di-axial to have higher strain energy?
You can't have both in a chair conformation!
If the methyl groups in 1,4-dimethylcyclohexane adopt a bis-axial orientation, they are trans and they stay trans after ring flip:
If your 1,4-dimethylcyclohexane is cis-substituted the orientation of the methyl groups is axial and equatorial, respectively: