Prochirality

Concept in stereochemistry

Prochirality is a concept in stereochemistry that describes a situation where a molecule is not chiral but can become chiral through a single alteration, such as the replacement of an atom or group. This concept is important in the study of enzyme reactions and asymmetric synthesis.

Definition

A molecule is considered prochiral if it can be converted from an achiral to a chiral molecule in a single step. This typically involves the introduction of a new stereocenter or the conversion of a prochiral center into a chiral center.

Prochiral Centers

A prochiral center is an atom in a molecule that can be converted into a chiral center by changing one of its substituents. For example, a carbon atom bonded to two identical groups and two different groups is a prochiral center. By replacing one of the identical groups with a different group, the carbon becomes a chiral center.

Prochirality in Enzymatic Reactions

Illustration of prochirality in a molecule.

Enzymes often interact with prochiral substrates, selectively converting them into chiral products. This selectivity is crucial in biochemistry, where the chirality of molecules can affect their biological activity. Enzymes can distinguish between the two faces of a prochiral molecule, leading to the formation of a specific enantiomer.

Prochirality in Asymmetric Synthesis

In asymmetric synthesis, prochiral molecules are often used as starting materials. The goal is to selectively produce one enantiomer over the other, which is achieved by using chiral catalysts or reagents that can differentiate between the two faces of the prochiral molecule.

Applications

Prochirality is a key concept in the design of pharmaceuticals, where the chirality of a drug can significantly influence its efficacy and safety. Understanding prochirality allows chemists to design synthetic routes that produce the desired enantiomer of a drug.

Related pages

• Chirality (chemistry)
• Stereochemistry
• Enantiomer
• Asymmetric synthesis