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

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Answer 1 · 2016-03-07T01:30:14

You follow a series of steps.

Step 1. Draw the structure of hexane.

Hexane

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

Wedge-dash

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.

Staggered Y

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.

Hexane 2,3

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