A catalytic domino reduction–imine formation–
intramolecular cyclization–oxidation for the general synthesis
of a wide variety of biologically relevant N-polyheterocycles,
such as quinoxaline- and quinoline-fused derivatives, and
phenanthridines, is reported. A simple, easily available, and
environmentally friendly dioxomolybdenum(VI) complex has
proven to be a highly efficient and versatile catalyst for
transforming a broad range of starting nitroarenes involving
several redox processes. Not only is this a sustainable, stepeconomical
as well as air- and moisture-tolerant method, but
also it is worth highlighting that the waste byproduct
generated in the first step of the sequence is recycled and
incorporated in the final target molecule, improving the
overall synthetic efficiency. Moreover, selected indoloquinoxalines
have been photophysically characterized in
cyclohexane and toluene with exceptional fluorescence
quantum yields above 0.7 for the alkyl derivatives.
