The stable form of trans-1, 4 dimethylcyclohexane is represented as:

Options

A.
B.
C.
D.

Answer

C

Explanation

First of all, there are two different dimethylcyclohexanes. One has both methyl substituents on the same side of the cyclohexane ring, it is the cis isomer (cis is Latin for "on this side"). The other has the two methyl substituents on opposite sides of the ring, it is the trans isomer (trans is Latin for “across”). cis-1, 4 dimethylcyclohexane and trans -1, 4 dimethylcyclohexane are called geometric isomers of cis-trans stereoisomers - they have the same atoms, and the atoms are linked in the same order, but they differ in the spatial (stereo) arrangement of the atoms.

cis-1, 4-dimethylcyclohexane trans-1, 4 dimethylcyclohexane First we will determine which of the two chair conformers of cis- 1, 4-dimethyl cyclohexane is more stable. One chair conformer has one methyl group in an equatorial position and one methyl group in an axial position. The other chair conformer also has one methyl group in an equatorial position and one methyl group in an axial position. Therefore, both chair conformers are equally stable.