More about the Diels-Alder reaction


This basic Diels-Alder reaction is very slow, but substituents on the reactants can increase the rate (you’ll learn about these effects in the Organic Chemistry course). 


In all cases the basic components (a diene and a dienophile) are the same:



Ring formation is usually favoured because two p-bonds on the left are replaced by two s-bonds on the right. 

·                The Diels-Alder reaction is a pericyclic reaction. 

·                Pericyclic reactions are a class of organic reactions, different from ionic or radical reaction mechanisms. 

·                Pericyclic reactions have cyclic transition state structures, and they are concerted reactions, i.e. all the bond-breaking and making takes place at once in a single step. 


The transition state for the Diels-Alder reaction