Cyclo-elimination
Cyclo-elimination , often also called cycloreversion , is the reversal (reverse reaction, counter-reaction) of the cycloaddition and usually takes place in concert. 2,5-Dihydrothiophendioxid breaks down, for example, in boiling xylene with reversal of a [4 + 1] cycloaddition to 1,3-butadiene and sulfur dioxide :
It is a [4 + 1] cycloreversion. [3 + 2] cycloreversions and [4 + 2] cycloreversions are also known. So forms cyclopentadiene by heating dicyclopentadiene . This cycloelimination is a reverse of the dimerization of cyclopentadiene and is also known as the retro-Diels-Alder reaction .
Individual evidence
- ^ Siegfried Hauptmann : Reaction and Mechanism in Organic Chemistry , BG Teubner, Stuttgart, 1991, p. 131, ISBN 3-519-03515-4 .