Molybdenum‐Catalyzed Direct Synthesis of Pyrroles from Nitroarenes with Glycols as Reductants

A molybdenum‐catalyzed synthesis of N‐(hetero)aryl pyrroles directly from inexpensive and commonly available (hetero)nitroarenes via reduction with pinacol and annulation with 1,4‐dicarbonyls or cyclobutane‐1,2‐diols has been described. The process does not require an inert atmosphere and tolerates the presence of air and water. This non‐noble catalytic system shows high chemoselectivity, allowing a diverse range of potentially reducible functional groups such as alkynes, alkenes, halogens, cyano, and carbonyls. Moreover, this strategy enables the reuse of a waste byproduct as reactant, facilitating the formation of challenging 1,4‐dicarbonyls from accessible cyclobutane‐1,2‐diols used as reducing agents.