ABSTRACT
This chapter focuses on applications of palladium (Pd) for the generation of many six-membered nitrogen (N)-heterocycles. Heterocycles and implicit nitrogen-containing heterocycles are becoming very important in all aspects of applied and pure chemistry. For many decades, N-heterocycles are utilized as medicinal compounds, and form the basis for various drugs like captopril, morphine, and vincristine. The six-membered heterocycles like substituted pyridines possess a wide range of pharmacological activity. A number of six-, seven-, and eight-membered nitrogen and oxygen heterocycles were synthesized regioselectively in good yields under very mild conditions. A number of N-heterocycles such as isoquinoline and pyridine were produced by a Pd-catalyzed iminoannulation of internal alkynes. The N-containing heterocycles were produced diastereo-and enantioselectively by a one-pot ruthenium -catalyzed enyne coupling of starting substrate followed by asymmetric carbon-nitrogen bond formation in the presence of Pd catalyst. H. W Fruhauf and co-workers used 1,1-dimethylallene and cyclopalladated a-tetralone ketimines for the synthesis of nitrogen heterocycles using stoichiometric Pd.
