ABSTRACT
Nitrogen (N)-heterocycles are a special group of organic compounds found in various pharmacologically active synthetic and natural products. The nature has provided countless chemical substances which are biologically and structurally relevant. Fused six-membered nitrogen-containing heterocycles like benzimidazoisoquinolines and benzimidazoquinazolines are potent anti-tumor agents. The phenanthridine derivatives were produced by coupling reaction of N-sulfonyl-2-aminodiphenyls with electron-deficient alkenes under air in the presence of palladium (Pd) acetate and copper acetate. However, upon implementation of an electron-rich N-heterocyclic carbene ligand, excellent yields of a number of functionalized five- and six-membered rings were obtained with varying tethers such as amine, ether, alkyl and amide moieties. R. Grigg synthesized phenanthrene-type heterocyclic compounds through a cycloaddition in the presence of rhodium(I) catalyst followed by a direct arylation of newly produced aromatic functionality with Pd catalyst. D. Alberico et al. produced annulated N-containing heterocyclic compounds by direct arylation reactions.
