Cyclohexane can be drawn flat, , but that masks the true shape of cyclohexane. In order to understand several problems in organic chemistry you will need to look at the possible conformations of cyclohexane. The chair conformation is most stable. Learn how to draw a chair conformation on paper. Every cyclohexane derivative has two possible chair conformations that interconvert rapidly at room temperature. In order for one chair conformation to change into the other it must pass through a boat conformation.

The two chair conformations are exactly the same for unsubstituted cyclohexane BUT watch carefully to see what happens to 1,2,3,4,5,6-hexadeuterocyclohexane. Watch the interconversion, while carefully following the Deuterium atoms (shown in orange). Each Deuterium starts off in an axial position in the original chair conformation and winds up being equatorial in the second chair conformation.

Turn on the space-filling option (under preferences) and note the 1,3-diaxial steric interaction between the axial methyl group and two of the axial hydrogens. Look down a C-C bond axis and draw a Newman Projection that shows a gauche interaction. Draw another Newman Projection down the same C-C bond axis for the second chair conformation. Are there any gauche interactions with the methyl group?