ABSTRACT
Five-membered nitrogen (N)-heterocyclic compounds are very important in a number of applications and occur in a diversity of drugs and natural products. Aromatic five-membered N-heterocycles containing one to four nitrogen atoms include pyrroles, pyrazoles, imidazoles, 1.2.3- triazoles, 1,2,4-triazoles, and tetrazoles. Heterocycles, especially N- and oxygen (O)-containing heterocycles, are most important class of compounds in agrochemical and pharmaceutical industries. Aromatic heterocycles were synthesized by trapping of substrate. Heterocycles were synthesized using alkenyl aziridines and epoxides via inter- and intramolecular carbon-heteroatom bond forming reactions. Oximes and their derivatives are widely used in organic synthesis as key intermediates in the preparation of a variety of heterocycles. The N-heterocycles were generated through palladium-catalyzed carbonylative sequence which involved Wacker-type anti-aminopalladation of alkynes, alkenes, or allenes. There are several other classes of heterocycles that could potentially be generated from palladium-catalyzed carboamination reactions.
