DIELS–ALDER THEORY

Otto Diels and Kurt Alder received the Nobel Prize in Chemistry in 1950 for discovering the reaction between a conjugated diene and an alkene.
reaccion-diels-alder

Diels-Alder is a stereospecific reaction, it produces a single diastereoisomer. To draw the stereoisomer formed in a Diels-Alder, three rules are followed:

1. Diels-Alder preserves the stereochemistry of the dienophile .
If the alkene is cis, the substituents remain cis in the final product.
estereoquimica-diels-alder

Diels-Alder is a stereospecific reaction, it produces a single diastereoisomer. To draw the stereoisomer formed in a Diels-Alder, three rules are followed:

 
1. Diels-Alder preserves the stereochemistry of the dienophile .
If the alkene is cis, the substituents remain cis in the final product.
estereoquimica-diels-alder

Alkynes can act as dienophiles in the Diels-Alder reaction. The reaction between diene and alkyne forms a 1,4-cyclohexadiene.

 
diels-alder-alquinos

The reverse reaction to Diels-Alder is called retro-Diels-Alder. Diels-Alder adducts decompose on heating into the diene and dienophile that formed them.

retro-diels-alder

The intramolecular Diels Alder reaction occurs when the diene and the dienophile belong to the same molecule.

diels alder intramolecular

Alkenes in the presence of light undergo cycloaddition reactions to form four-membered rings. These reactions are called [2 + 2] cycloadditions.

photochemical reactions 01

Both 1,3-butadiene (4n) and 1,3,5-hexatriene (4n + 2) cyclize with light or heat to give cyclobutene and 1,3-cyclohexadiene, respectively.

electrocyclic reactions 01

Like Diels-Alder, electrocyclic reactions are concerted and stereospecific.