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In my BR orgo book, it says that Cis-1,3-dimethylcyclohexane is less stable than trans-1,4-dimethylcyclohexane which is less stable than trans-1,2-dimethylcyclohexane.
I understand why the cis one is the least stable out of all of them, because it is the only interaction that places both substituents in axial orientation pointing in the same direction. However, I do not see why trans-1,4-dimethylcyclohexane is more stable than trans-1,2-dimethylcyclohexane.
Both of these structures have the substituents in opposite axial orientations (one pointing up, and one pointing down). However, aren't the 1-4 substituents further apart, meaning there is less steric interaction? It says that the fact that 1-2 has gauche interactions between the bulkiest groups makes it have less of an energy difference between the axial and equatorial conformations (more stable I think). I would think the gauche interaction would decrease the stability.
I understand why the cis one is the least stable out of all of them, because it is the only interaction that places both substituents in axial orientation pointing in the same direction. However, I do not see why trans-1,4-dimethylcyclohexane is more stable than trans-1,2-dimethylcyclohexane.
Both of these structures have the substituents in opposite axial orientations (one pointing up, and one pointing down). However, aren't the 1-4 substituents further apart, meaning there is less steric interaction? It says that the fact that 1-2 has gauche interactions between the bulkiest groups makes it have less of an energy difference between the axial and equatorial conformations (more stable I think). I would think the gauche interaction would decrease the stability.
