Question

Question: a.Draw the three staggered and three eclipsed conformations that result from rotation around the bond labeled in red using Newman projections. b. Label the most stable and least stable conformation.

Short answer

Answer

a. The three staggered and three eclipsed conformations are shown below:

b. The most stable and the least stable conformations are shown below:

Step-by-step solution

Staggered and eclipsed conformation

These are the two different conformations observed by changing the dihedral angle. In other words, it is done by rotating one carbon atom and fixing the other one.

Explanation for a

a. The Newman projection of the given compound is shown below:

Eclipsed conformation

The staggered and eclipsed conformations of the given compound are observed by rotating the back carbon and fixing the front carbon atom as shown below:

Conformation of the given compound

Explanation for b

b. The conformations that have less repulsion between the methyl groups are considered the most stable conformations. Thus, conformations IV and VI are the most stable conformations, as shown below:

Most stable conformation

The conformations that have more repulsion between the methyl groups are considered the least stable conformations. Thus, conformations I and III are the least stable conformations, as shown below:

Least stable conformation