The study of catalyst free and copper catalyzed reactions of cyanochromenes and sodium azide

Two different roles of sodium azide under two different conditions are described here along with the plausible mechanisms. When sodium azide was treated with cyanochromenes under catalyst free conditions, the azide anion acted as a base. Hence, a base mediated rearrangement of cyanochromenes was resulted in formation of benzofuran derivatives. However, in the presence of catalytic amount of CuI the azide anion acted as a diene to produce chromenotetrazoles.