Aza-Diels-Alder Reaction: An Efficient Approach for Construction of Heterocycles

Aza heterocycles comprise some rousing structures in biological systems. The aza-Diels-Alder reaction is a [4Π +2Π] cycloaddition, involving a nitrogen atom in either diene or dienophile or both for the generation of unsaturated N-hexacycles. Although aza- Diels-Alder reaction has made a wonderful journey through different stages of development it is still considered as one of the hot topics of research because of procedural simplicity, high atom economy, regio- and stereoselectivity. Building blocks of many pharmaceutically as well as pharmacologically vital heterocycles have come out as a result of application of aza-Diels-Alder protocol in numerous chemical reactions. This review article describes the state of the art of the aza-Diels-Alder reactions highlighting some of the very first discovery of this pericyclic reaction to most important modern developments. Our discussion is highly focused on awesome versions of aza- Diels-Alder reaction under selected and magnificent catalytic systems and, will provide readers an overview on versatility of this special branch of Diels-Alder reaction towards the creation of a flood of N-containing molecules. Keywords: Aza-Diels-Alder reaction, bifunctional organocatalyst, brønsted acid, cooperative catalysis, enzyme catalysis, green dimension, ionic liquid, lewis acid.