Diels-Alder reactions of 1-amino-1,3-dienes and related systems

Abstract In this account, Diels-Alder reactions of different 1-amino-1,3-dienes with dienophiles are considered. As 1-amino-1,3-dienes, dienamines, dienamides, 1,2-dihydropyridines, 2-pyridones and vinylic heterocycles, such as vinyl-pyrroles, pyrazoles, imidazoles, indoles, tetrahydropyridines and dihydropyridones are studied. As dienophiles, enals, acrylic, maleic and fumaric derivatives, quinones, tetracyanoethylene, dialkyl acetylenedicarboxylates, nitroolefins, nitrosobenzene and azocompounds play an important role. Synthetic applications of these inter or intramolecular, racemic or enantioselective reactions in order to prepare polycyclic nitrogen-containing heterocycles, are pointed out, specially in the preparation of naturally occurring and biologically active compounds mainly alkaloids. The most significant feature of the chemistry described in this account is the fact that this methodology represents a simple and selective way to get N-containing heterocyclic compounds in only one reaction step, creating at least two carbon-carbon bonds in a regio-, diastereo- and enantioselective fashion.