Newman projections are simply another way to draw organic molecules that specifically helps in visualizing conformational isomers. These projections are drawn by looking directly along a particular bond in the system (here a C-C bond) and arranging the substituents symmetrically around the atoms at each end of that bond. The protocol requires that the atoms within the central bond is defined as shown below:
In order to draw a Newman projection from a wedge-dash diagram, it is useful to imagine putting your "eye" in line with the central bond in order to look along it. Let's work through an example, consider drawing a Newman projection by looking at the following wedge-dash diagram of propane from the left hand side.
- First draw the dot and circle to represent the front and back C respectively
- Since the front carbon atom has an H atom in the plane of the page pointing up we can add that first
- The back carbon atom has an H atom in the plane of the page pointing down
- Now add the other bonds to each C so that it is symmetrical
- The groups / bonds (blue) that were forward of the plane of the page in the original wedge-dash diagram are now to our right
- Those behind (green) the plane are now to our left