Question

How can I convert the bond-line structure of 2-methylhexane to a Newman projection viewed along the C3-C4 bond?

Answer 1

You follow a series of steps.

Explanation:

Step 1. Draw the structure of 2-methylhexane.

Step 2. Convert to a wedge-dash structure at `"C-3"` and `"C-4"`.

Step 3. Identify the groups on `"C-3"` and `"C-4"`.

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

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

The groups on `"C-3"` are `"H"`, `"H"`, and `"CH(CH"_3)_2`. Those on `"C-4"` are `"H"`, `"H"`, and `"CH"_3"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 right.

The groups on `"C-3"` go on the front carbon atom. Put the `"CH(CH"_3)_2`group on the bottom. The two `"H"` atoms go on the other bonds.

The groups on `"C-4"` go on the back carbon. The bulky `"CH"_3"CH"_2` group goes on the top, and the two `H` atoms go on the other bonds.

This is the most stable conformer. It has the bulky isopropyl group anti to an ethyl group.