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# Are there gauche interactions in cyclohexane?

## Are there gauche interactions in cyclohexane?

Because the methyl groups are not on adjacent carbons in the cyclohexane rings gauche interactions are not possible.

How many gauche butane interactions does cyclohexane have?

There are two gauche butane interactions in axial methyl- cyclohexane. Each gauche butane contributes 0.9 kcal/mol of instability, meaning the axial methyl is roughly 1.8 kcal/mol less stable than the equatorial. Complexity continues to grow as the number of substituents increases.

### How do you identify gauche interactions?

When we sight down a carbon-carbon single bond and draw a Newman projection of a particular conformation, any two groups on the adjacent (vicinal) carbons that have a dihedral angle of 60° between them are said to have a gauche relationship.

What is a gauche interaction?

Gauche: The relationship between two atoms or groups whose dihedral angle is more than 0o (i.e., eclipsed) but less than 120o (i.e., the next eclipsed conformation). A conformation which has one or more gauche interactions is can be called a gauche conformation.

#### How many gauche interactions are present?

Thus there are four gauche butane interactions.

What is a gauche butane interaction?

The gauche interaction occurs in butane occurs when the two methyl groups have dihedral angles of 60° and 300° and arises because the methyl groups are still quite close together (about 3.1 Å, compare to 2.9 Å) for the syn– conformation. The strain energy of the gauche interaction is about 0.9 kcal/mol.

## What is a Newman projection for cyclohexane?

A Newman projection for cyclohexane is two Newman projections joined together. For the chair form, view the diagram so that the carbon atom nearest to you ( C-6) is “up”, C-2 is “behind” C-1, and C-4 is “behind” C-5. Draw side-by-side projections of the C1-C2 and C5-C4 bonds.

How do you add C6 and C3 to Newman projections?

Join the two diagrams with the front carbon ( C-6) at the top and the rear carbon ( C-3) at the bottom. Add the groups (here they are H atoms) to the bonds extending from the Newman projections.

### How to draw the worst Newman projection?

( Steps(for(Drawing(the(Worst(Newman(projection( Summary:((Draw(eclipsed(sticks;(install(substituents(appropriately( 1. Draw an eclipsed Newman projection, with three sticks on the “back” carbon and three on the “front”. Have a stick up on both the back and front carbons. 2. Draw your biggest substituent on the back carbon on the “up” stick 3.