Mo‐Catalyzed Synthesis of N‐Polyheterocycles From Functionalized Nitroarenes and Aldehydes

Abstract

The direct preparation of nitrogen-containing polyaromatic heterocycles in a single operational step from readily availablenitroarenes represents an attractive and sustainable alternative to traditional multistep approaches. In this context, this workdescribes an efficient and versatile methodology for the synthesis of fused N-polyheterocyclic scaffolds from functionalizednitroarenes and aldehydes catalyzed by dioxomolybdenum(VI) complexes and employing pinacol as a readily available andenvironmentally benign reductant. The protocol integrates nitro reduction, imine formation, and intramolecular cyclization ina single operational sequence. Careful fine-tuning of the reaction conditions proved crucial to minimizing competing pathways.This molybdenum-catalyzed strategy exhibits broad substrate scope, accommodating aromatic, aliphatic, and α,β-unsaturatedaldehydes, and enabling access to a variety of pharmaceutically relevant frameworks, such as pyrrolo[1,2-a]quinoxalines,indoloquinoxalines, γ-carbolines, imidazoquinolines, and phenanthridines.