Pericyclic reaction facts for kids

A pericyclic reaction is a special kind of chemical reaction in organic chemistry. Imagine atoms moving around in a circle to form a new molecule. In these reactions, the atoms move at the same time, in a very organized way, through a ring-shaped arrangement. It's like a dance where all the dancers move together in a circle to change their formation.

Most pericyclic reactions are rearrangement reactions, meaning the atoms in a molecule simply rearrange themselves to form a different molecule.

Some important types of pericyclic reactions include:

• Electrocyclic reactions
• Cycloadditions
• Sigmatropic reactions
• Group transfer reactions
• Cheletropic reactions
• Dyotropic reactions

Pericyclic reactions can often go both ways, like a seesaw. They try to reach a balance. However, if one side (the product) is much more stable, the reaction will mostly go in that direction.

Sometimes, chemists debate if a reaction is truly pericyclic. This is because some reactions look similar but happen in different steps, or they need a metal to help them. When a metal helps, it often means the reaction isn't truly "concerted" (all happening at once).

Pericyclic reactions can also happen in reverse. These are called "retro" pericyclic reactions.

Pericyclic Reactions in Living Things

Pericyclic reactions are not just found in chemistry labs. They also happen inside living organisms! Here are a few examples:

• A Claisen rearrangement helps make prephenate from chorismate. This is important for almost all organisms that can make their own food.
• A type of sigmatropic shift happens when precorrin-8x changes into hydrogenobyrinic acid.
• When your body makes vitamin D, a light-driven electrocyclic ring opening and a sigmatropic shift occur.
• An enzyme helps change Isochorismate into salicylate and Pyruvate through a true pericyclic reaction.

Isochorismate Pyruvate Lyase converts Isochorismate into salicylate and Pyruvate

Images for kids

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  This image shows how atoms move in a pericyclic reaction, like a circular dance.

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  This diagram shows how electrons move in a pericyclic reaction.

See Also

• Woodward–Hoffmann rules

In Spanish: Reacción pericíclica para niños