Reactions of triazines and tetrazines with dienophiles (Review)

Information on the development of a valuable synthetic methodology based on inverse electron-demand Diels–Alder reaction in the series of π-deficient azadienes (triazines and tetrazines) is summarized and classified. By this method it is possible to obtain mono-, di-, and triazines containing functional substituents both from the initial azine and from the dienophile. Such reactions are often the simplest and even the only possible method for the synthesis of substances with properties suitable for practical applications.