Chirality is an important property in pharmaceuticals and is receiving increasing attention in cosmetics. What is it, and what is its significance in these two areas?
Before we answer these questions, you must remember that molecules are three dimensional (3-D), and saturated organic molecules are tetrahedral in shape. When we draw moleculare structures, the atoms or groups attached to a central saturated carbon will be viewed as being in the plane of the paper, above or below the plane. With this in mind, we define chirality as any molecule whose 3-D structure cannot be superimposed on its mirror image. Classically, the analogy is of a person's left and right hands, which are mirror images and cannot be superimposed on each other.