Non-classical effective methods for reduction of heteroaromatic compounds

The review summarizes the known data on various methods for saturation and dearomatization of heterocyclic moieties, forming diverse aromatic compounds. Since the classical hydrogenation of substrates with molecular hydrogen has a number of fundamental drawbacks that hinder both its use at the laboratory level and its widespread implementation in industrial production, the main attention is paid to non-classical methods described in the literature over the last 20–25years. The methods of ammonia-free Birch reduction, transfer hydrogenation, reduction by Hantzsch esters and some other reactions involving heterocyclic compounds are summarized and systematized. It is shown that such methods of reduction or dearomatization of heterocycles can in some cases be more efficient than classical procedures. The bibliography includes 173 references.