Dr Steward’s Quiz #4 – (Newman projections / chair conformations) KEY
1. Determine the number of each type of carbon in the following structures:
primary (1°): 5
secondary (2°): 4
tertiary (3°): 1
quaternary (4°): 2
primary (1°): 4
secondary (2°): 0
tertiary (3°): 2
quaternary (4°): 0
primary (1°): 4
secondary (2°): 0
tertiary (3°): 2
quaternary (4°): 0
primary (1°): 3
secondary (2°): 5
tertiary (3°): 1
quaternary (4°): 1
2. Finish each Newman Projection to correctly represent the following molecule.
3. Use the following structure to draw Newman Projections (each subsequent projection with
the back carbon rotated 60° clockwise). Explicitly label all H’s, CH3’s, and CH(CH3)2. The
arrow denotes the “front” carbon.
Highest


Label the highest and lowest energy Newman Projections from above.
Do any of the Newman projections from above have the same energy? No.
4. Draw a chair conformation for the following wedge/dash structure. Also draw the correct
ring-flip conformation. Circle the conformation that is higher in energy. Explain why it is
higher in energy.
The first chair conformation because of 1,3diaxial interactions from the bulky axial
groups. The second chair structure puts the
bulkier groups in equatorial positions (only
the H’s are axial).
Lowest
5. Determine the relationship between the chair conformation in the box and the other
representations: chair flips (only for chair conformations), stereoisomers, constitutional
isomers or the same):
Stereo
Const
Chair
Same
Stereo
Stereo
Stereo
Const