How to Draw a Newman Projection

Before we can talk about drawing Newman projections, we need to first review one aspect of drawing bond-line stractures that we did not cover in Chapter 1. To show how groups are positioned in 3D space, we often use wedges and dashes  

Do not be confused by whether the dash is drawn on the right or left  

Now that we understand what the dash and wedge mean, let s consider what the molecule would look like from a slightly different angle  

You would see the three groups like this, and you would not see the back carbon atom, because the carbon atom in front would be covering it up (again, like the moon covers the sun during a solar eclipse). Let s try to draw that back carbon that we cannot see, and by convention, we will draw it as a big circle  

Now we place the three groups that are on the back carbon atom into our drawing. There is one methyl group and two hydrogen atoms. If we put them into our drawing, then we get our Newman projection. It looks like this  

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How To Name an Alkane Using the lUPAC System 121 How To Name a Cycloalkane Using the lUPAC System 125 How To Draw a Newman Projection 132 How To Draw the Chair Form of Cyclohexane 139 How To Draw the Two Conformations for a Substituted Cyclohexane How To Draw Two Conformations for a Disubstituted Cyclohexane Stereochemistry... 

Newman projections illustrate the conformation of molecules viewed along the length of a bond. See p. 364 if you need reminding of how to draw and interpret them. 

How To Name Alkenes and Cycloalkenes 156 How To Name Alkynes 158 4.8A Newman Projections and How To Draw Them 162 4.8B How To Do a Conformational Analysis 163... 

The bond angles are approximately 109.5° in both the chair and the boat forms of cyclohexane. However, the chair form of cyclohexane is slightly lower in energy. Why is this To answer this question, we will first describe how to draw the chair form of cyclohexane and then use a Newman projection to provide the insight needed. 

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