Controversy exists as to whether the mechanism for this reaction is concerted and synchronous, concerted and asynchronous, or stepwise.
Controversy exists as to whether the mechanism for this reaction is concerted and synchronous, concerted and asynchronous, or stepwise. Imidazolidinone complexes can produce the exo product in high enantiomeric excess, but for most reagents, an endo attack is strongly preferred. The rate of this reaction can be modified by electron donating or withdrawing substituents which reduce the gap between the HOMO and LUMO of the reactants. This reaction was first observed in 1928 between maleic anhydride and butadiene , giving cis-1, 2, 3, 6-tetrahydrophthalic anhydride. For ten points, name this 4+2 addition that reacts a diene and a dienophile to produce a cyclic alkene, named for its two discoverers.
Controversy exists as to whether the mechanism for this reaction is concerted and synchronous, concerted and asynchronous, or stepwise.
Diels-Alder reaction