the diels-alder reaction is an example of the cycloaddition class of reactions.
the diels-alder reaction is an example of the cycloaddition class of reactions.
the diels-alder reaction is an example of which class of reactions?
cycloaddition
in organic chemistry, the diels–alder reaction is a chemical reaction between a conjugated diene and a substituted alkene, commonly termed the dienophile ("also spelled dieneophile"), to form a substituted cyclohexene derivative. it is the prototypical example of a pericyclic reaction with a concerted mechanism. more specifically, it is classified as a thermally-allowed [4+2] cycloaddition with woodward–hoffmann symbol [4 + 2]. it was first described by otto diels and kurt alder in 1928. for the discovery of this reaction, they were awarded the nobel prize in chemistry in 1950. through the simultaneous construction of two new carbon–carbon bonds, the diels–alder reaction provides a reliable way to form six-membered rings with good control over the regio- and stereochemical outcomes. consequently, it has served as a powerful and widely applied tool for the introduction of chemical complexity in the synthesis of natural products and new materials. the underlying concept has also been applied to π-systems involving heteroatoms, such as carbonyls and imines, which furnish the corresponding heterocycles; this variant is known as the hetero-diels–alder reaction. the reaction has also been generalized to other ring sizes, although none of these generalizations have matched the formation of six-membered rings in terms of scope or versatility. because of the negative values of δ"h"° and δ"s"° for a typical diels–alder reaction, the microscopic reverse of a diels–alder reactions becomes favorable at high temperatures, although this is of synthetic importance for only a limited range of diels-alder adducts, generally with some special structural features; this reverse reaction is known as the retro-diels–alder reaction.
diels–alder reaction
section::::variants on the classical diels–alder reaction.









































section::::variants on the classical diels–alder reaction.:hetero-diels–alder.









































diels–alder reactions involving at least one heteroatom are also known and are collectively called hetero-diels–alder reactions. carbonyl groups, for example, can successfully react with dienes to yield dihydropyran rings, a reaction known as the oxo-diels–alder reaction, and imines can be used, either as the dienophile or at various sites in the diene, to form various "n"-heterocyclic compounds through the aza-diels–alder reaction. nitroso compounds (r-n=o) can react with dienes to form oxazines. chlorosulfonyl isocyanate can be utilized as a dienophile to prepare the vince lactam.
diels–alder reaction