Q.4-25 - Organic Chemistry (Mcmurry)

Question

The following cyclohexane derivative has three red, green, and blue substituents. Identify each substituent as axial or equatorial, and identify each pair of relationships (red–blue, red-green, and blue-green) as cis or trans.

Step-by-Step Solution

Answer

Green is at the axial position, and blue and red are at the equatorial position. The relationships are as follows: Red–blue- Trans, Red-green- Trans, and Blue–green- Cis.

Definition of Chair confirmation

Chair conformation structure for the six-membered ring is when atoms 2, 3, 5, and 6 lie in the same plane, atom 1 lies above the plane, and atom 4 lies below the plane.

Explanations of Axial and equatorial positions

Axial bonds are the bonds that are perpendicular or vertical to the ring plane. Equatorial bonds are approximately horizontal in the plane of the ring. 

Cis and Trans configuration

Cis configuration is when two groups are on the same face of the ring, and trans configuration is when the groups are on opposite faces. Both isomers are stable, and neither can be converted into the other without breaking and reforming chemical bonds.

Positions of groups

Here, green is present vertical to the rin, at the axial position, and blue and red are present approximately horizontal in the plane of the ring, at the equatorial position.

Relation between groups

The relationships are as follows:

Red–blue - Trans as blue is pointing outward and red inward.

Red-green - Trans as green is pointing outward and red inward.

Blue-green - Cis as both are pointing outward.