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The retro-Diels–Alder reaction (rDA reaction) is the reverse of the Diels–Alder (DA) reaction, a [4+2] cycloelimination. It involves the formation of a diene and dienophile from a cyclohexene . It can be accomplished spontaneously with heat, or with acid or base mediation.
A retro-Diels Alder reaction of the diphenylanthracene peroxide can also yield singlet oxygen, along with an diphenylanthracene: [22] Retro-Diels Alder formation of singlet oxygen. A third method liberates singlet oxygen via phosphite ozonides, which are, in turn, generated in situ such as triphenyl phosphite ozonide.
Asymmetric Diels-Alder reaction is one step in the biosynthesis of the statin lovastatin. [60] The retro-Diels–Alder reaction is used in the industrial production of cyclopentadiene. Cyclopentadiene is a precursor to various norbornenes, which are common monomers. The Diels–Alder reaction is also employed in the production of vitamin B6.
Formally it is a [4+2] cycloaddition reaction and exists in a huge range of forms, including the inverse electron-demand Diels–Alder reaction, hexadehydro Diels–Alder reaction and the related alkyne trimerisation. The reaction can also be run in reverse in the retro-Diels–Alder reaction.
The normal electronic demand for the Diels–Alder reaction calls for an electron-rich diene to react with an electron-poor olefin (or "dienophile"), while the inverse electron-demand Diels–Alder reaction takes place between the opposite case of an electron-poor diene and a very electron-rich dienophile. The photoredox case, since it takes ...
Reactions can be either photochemical or thermal. Reactions can be either ring-opening or ring-closing (electrocyclization). Depending on the type of reaction (photochemical or thermal) and the number of pi electrons, the reaction can happen through either a conrotatory or disrotatory mechanism.
In the Diels-Alder cycloaddition, the endo diastereoselectivity due to secondary orbital interactions is usually observed. In 1,3-dipolar cycloadditions, however, two forces influence the diastereoselectivity: the attractive π-interaction (resembling secondary orbital interactions in the Diels-Alder cycloaddition) and the repulsive steric ...
In the history of the Nobel Prize in Chemistry awards have been given for the invention of specific organic reactions such as the Grignard reaction in 1912, the Diels–Alder reaction in 1950, the Wittig reaction in 1979 and olefin metathesis in 2005.