[4+2] Cycloadditions (Diels‐Alder Reactions)

Abstract

In thermal and Lewis acid-catalyzed Diels-Alder cycloaddition reactions diene and dienophile react in a suprafacial concerted process predicted by the Woodward-Hoffinann rules.'eg Therefore, the double bond configuration of the dienophile is retained in the cycloadducts. In asymmetric Diels-Alder reactions up to four stereogenic centers can be formed stereoselectively in a single reaction step.