Iron-Catalyzed Intermolecular Amination of Benzylic C(sp3)–H Bonds

A catalytic system for intermolecular benzylic C(sp3)-H amination is developed utilizing 1,2,3,4-tetrazole as a nitrene precursor via iron catalysis. This method enables direct installation of 2-aminopyridine into the benzylic and heterobenzylic position. The method selectively aminates 2° benzylic C(sp3)-H bond over the 3° and 1° benzylic C(sp3)-H bonds. Experimental studies reveal that the C(sp3)-H amination undergoes via the formation of a benzylic radical intermediate. This study reports the discovery of new method for 2-pyridine substituted benzylamine synthesis using inexpensive, biocompatible base metal catalysis that should have wide application in the context of medicinal chemistry and drug discovery.