Test 1: Plane of Symmetry

The simplest test for chirality is symmetry. If a molecule has an internal line of symmetry, it is achiral

  • Unfortunately, this test is only practical for rings.

Example: Does the following molecule contain a stereogenic center? Is it chiral?

 

1m

This is what we call a Hawthorne Projection. It’s a way to visualize rings in 3D. It’s really easy to tell if these molecules have a plane of symmetry or not. 

Example: Does the following molecule contain a stereogenic center? Is it chiral?

 

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This is a 2D ringed structure. It’s super easy to predict a plane of symmetry on this one. 

Example: Does the following molecule contain a stereogenic center? Is it chiral?

 

2m

The plane of symmetry is allowed to split atoms! Just look for any line that can create equal images on both sides. 

Example: Does the following molecule contain a stereogenic center? Is it chiral?

 

3m

Do you think TEST 1 will work well on this molecule? Why or why not?