INTRODUCTION

 

•	Stereoisomers are molecules whose atomic connectivity is the same but whose three-dimensional arrangement of atoms in space is different.

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This has sweeping implications in biological systems. For example, most drugs are often composed of a single stereoisomer of a compound, and while one stereoisomer may have positive effects on the body (since it has the right three-dimensional shape to bind to the protein receptor), another stereoisomer may not bind, or could even be toxic. An example of this is the drug thalidomide which was used during the 1950s to suppress morning sickness. The drug, unfortunately, was prescribed as a mixture of stereoisomers, and while one stereoisomer actively worked on controlling morning sickness, the other stereoisomer caused serious birth defects. Ultimately the drug was pulled from the marketplace.

•	Because of these implications, a great deal of work done by synthetic organic chemists is in devising methods to synthesize compounds that are purely one stereoisomer.

•	The ability to visualise and manipulate molecules in three-dimensions is vitally important in order to study and understand the structural features that give rise to stereoisomerism.