Conformational analysis—CI : The gauche-hydrogen interaction as the basis of conformational analysis

It is concluded that the gauche-butane interaction which is one of the cornerstones of conformational analysis has been incorrectly interpreted as to origin, and that the gauche relationship between methyl (or methylene) groups is not the cause of the relative instability of gauche conformations. Rather, the gauche interactions between vicinal-2,3-hydrogens are mainly responsible. By the same taken, a substituent on a cyclohexane ring should not be said to have a preference for the equatorial position. Rather, the tertiary hydrogen has an energetic preference for an axial position, which leaves the substituent in the equatorial position by default. Several poorly understood phenomena are better interpreted on this basis.