How do you name alkanes from Newman projections?

To name an alkane from a Newman projection, you convert the projection to a line structure; then you write the IUPAC name.

EXAMPLE:

Name the alkane shown in the following Newman projection.

Solution:

One C atom is at the front of the circle. Another C atom hides behind the circle. You must trace the bonds through the structure.

Pick the longest chain from one of the three groups attached to the front C atom.

Since they are all CH₃ groups, pick one of them. Label that CH₃ carbon C-1.

C-1 attaches to C-2, the front carbon.

C-2 attaches to the other two CH₃ groups and to the hidden C-3. Label the front carbon C-2.

C-3 attaches to two H atoms and a CH₂CH₃ group. Pick the longest group (CH₂CH₃) to form the rest of the chain.

Label the CH₂ carbon as C-4.

Label the CH₃ carbon as C-5.

You now have the longest chain in the molecule.

Draw the line structure.

C-1 = CH₃ C-2 = C(CH₃)₂ C-3 = CH₂ C-4 = CH₂ C-5 = CH₃

Your structure should look something like the structure below.

Write the IUPAC name.

The alkane is 2,2-dimethylpentane.