Diels–Alder reaction facts for kids

Diels–Alder reaction
Named after	Otto Diels Kurt Alder
Reaction type	Cycloaddition
Reaction
conjugated (substituted) Diene + (substituted) Olefin ↓ (substituted) Cyclohexene
Identifiers
RSC ontology ID	RXNO:0000006 Y

The Diels–Alder reaction (DA) is a special chemical reaction. It happens between two different organic compounds. This reaction helps these compounds join together. They form a new compound with a six-sided shape. This new compound is called a cyclohexene.

Imagine one compound has two double bonds. These bonds are separated by one carbon atom. This is called a conjugated diene. It joins with another compound that has at least one double bond. This second compound is an alkene. Together, they create the cyclohexene, which looks like a ring.

Discovery of the Diels–Alder Reaction

This amazing reaction was found by two scientists. Their names were Otto Diels and Kurt Alder. They discovered it in 1928. Their work was very important.

In 1950, they won the Nobel Prize in Chemistry. This award was for their discovery of the Diels–Alder reaction.

Why the Diels–Alder Reaction is Useful

The DA reaction is very helpful for chemists. It allows them to make cyclohexenes easily. It does not need a lot of energy.

Cyclohexenes are important building blocks. They are used to create complex organic molecules. These molecules are used in many things. For example, one of the first uses was to make insecticides. These are chemicals that kill insects.

How the Reaction Works

The DA reaction creates a new ring-shaped compound. This ring has six sides. It forms when a compound with two double bonds (a diene) meets another compound with at least one double bond (an alkene).

Sometimes, the atoms in the new ring are not all carbon. This can still be a Diels–Alder reaction.

Reversible Reactions

Some Diels–Alder reactions can go both ways. This means they are reversible. The new ring can also break apart. When the ring breaks, it is called a retro-Diels–Alder reaction. Scientists often see these broken compounds when they study them. They use a method called mass spectrometry.

The "Mona Lisa" of Chemistry

Some chemists call the Diels–Alder reaction the 'Mona Lisa' of organic reactions. The Mona Lisa painting has a simple smile. But it might be more complex than it seems. In the same way, this reaction might be more complex than scientists know right now.

Helping the Reaction Happen

Certain chemicals can speed up the Diels–Alder reaction. These chemicals are called catalysts. Examples include Lewis acids. Some common Lewis acids are AlCl₃ and ZnCl₂. They help the reaction happen faster and more easily.

Images for kids

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  FMO analysis of the Diels–Alder reaction

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  Resonance structures of normal-demand dienes and dienophiles

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  Regioselectivity in normal (1 and 2) and inverse (3 and 4) electron demand Diels-Alder reactions

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  Endo and exo transition states for cyclopentadiene adding to acrolein; endo/exo product ratio for this and various other dienophiles

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  General form of Danishefsky, Brassard, and Rawal dienes

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  in situ generation of o-quinodomethanes

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  The reaction discovered by Diels and Alder in 1928.

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  Diels-Alder in the total synthesis of cortisone by R. B. Woodward

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  Diels-Alder in the total synthesis of prostaglandin F2α by E. J. Corey

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See also

In Spanish: Reacción de Diels-Alder para niños