stereoisomerejä

Stereoisomers are a type of isomer that have the same molecular formula and the same connectivity of atoms but differ in the three-dimensional arrangement of atoms in space. This difference in spatial arrangement leads to distinct physical and chemical properties.

There are two main types of stereoisomers: enantiomers and diastereomers. Enantiomers are stereoisomers that are non-superimposable mirror images of each other, much like left and right hands. They possess opposite configurations at all chiral centers. Diastereomers, on the other hand, are stereoisomers that are not mirror images of each other. This occurs when a molecule has two or more chiral centers, and the configurations differ at some but not all of them.

Chirality, the property of a molecule being non-superimposable on its mirror image, is central to stereoisomerism. Molecules with at least one chiral center are often chiral. The presence of stereoisomers is particularly important in biochemistry and pharmacology, as different stereoisomers of a molecule can exhibit vastly different biological activities, with one isomer being effective and another being inactive or even harmful. For example, thalidomide, a drug once prescribed for morning sickness, had one enantiomer that was therapeutic and the other that caused severe birth defects. Understanding and controlling stereochemistry is crucial in the synthesis of many pharmaceuticals and other complex organic molecules.