Question

How do you draw a Newman projection for hexane while sighting down `C_2-C_3`?

Answer 1

You follow a series of steps.

Explanation:

Step 1. Draw the structure of hexane.

Step 2. Convert it to a wedge-dash structure at `"C-2"` and `"C-3"`.

Step 3. Identify the groups on `"C-2"` and `"C-3"`.

The main chain of hexane is the horizontal zig-zag line of carbon atoms.

`"C-1"` is on the left.

The groups on `"C-2"` are `"H"`, `"H"`, and `"CH"_3`.

Those on `"C-3"` are `"H"`, `"H"`, and `"CH"_3"CH"_2"CH"_2`.

Step 4. Draw a template for a Newman projection.

Step 5. Attach the groups to the carbons of your template.

View the molecule from the upper left.

The groups on `"C-2"` go on the front carbon atom. Put the `"CH"_3` group on the bottom. The two `"H"` atoms go on the other bonds.

The groups on `"C-3"` go on the back carbon. The bulky `"CH"_3"CH"_2"CH"_2` group goes on the top, and the two `"H"` atoms go on the other bonds.

This is the most stable conformer, because it has the bulky methyl and propyl groups anti to each other.