Direct Synthesis of Pyrroles by Dehydrogenative Coupling of Diols and Amines Catalyzed by Cobalt Pincer Complexes

Herein, the first example of base‐metal‐catalyzed dehydrogenative coupling of diols and amines to selectively form functionalized 1,2,5‐substituted pyrroles liberating water and hydrogen gas as the sole by‐products is presented. The reaction is catalyzed by pincer complexes of earth‐abundant cobalt. A complex of an earth‐abundant metal is shown to catalyze the dehydrogenative coupling of diols and amines to form substituted pyrroles with liberation of H2 and water. Of the well‐defined PNNH–Co pincer complexes tested in the presence of tBuOK and NaHBEt3, complex 1 turned out to be the most effective. The reaction is applicable to a wide range of primary alkyl amines, benzylic amines, and aromatic amines, and to primary and secondary diols.