Answer
In both structures, the back carbon will have:
Up: Methyl (Me)
Right: Methyl (Me)
Left: Methyl (Me)
In the most stable structure, the front carbon will have:
Down: Methyl (Me)
Right: Methyl (Me)
Left: Methyl (Me)
In the less stable structure, the front carbon will have:
Up: Methyl (Me)
Right: Methyl (Me)
Left: Methyl (Me)
Work Step by Step
1. For both most and less stable conformations, draw the atoms connected to the back carbon. (Represented by the circle.)
In this case:
Up: Methyl (Me)
Right: Methyl (Me)
Left: Methyl (Me)
2. Identify the largest group connected to the front carbon, and for the back carbons:
In this case:
Front carbon: Methyl (Me)
Back carbon: Methyl (Me)
3. Now, for the most stable one, we will rotate only the groups/atoms on the front carbon (The point on the center.), trying to put the largest groups we identified as distant as possible.
In this case, the front carbon will have:
Down: Methyl (Me)
Right: Methyl (Me)
Left: Methyl (Me)
4. Now, for the most stable one, we will rotate only the groups/atoms on the front carbon (The point on the center.), trying to put the largest groups we identified as close as possible.
In this case, the front carbon will have:
Up: Methyl (Me)
Right: Methyl (Me)
Left: Methyl (Me)
