Synthesis of aziridines from alkenes and aryl azides with a reusable macrocyclic tetracarbene iron catalyst

Abstract

A new iron aziridination catalyst supported by a macrocyclic tetracarbene ligand has been synthesized. The catalyst, [((Me,Et)TC(Ph))Fe(NCCH(3))(2)](PF(6))(2), was synthesized from the tetraimidazolium precursor ((Me,Et)TC(Ph))(I)(4) and characterized by NMR spectroscopy, electrospray ionization mass spectrometry, and single-crystal X-ray diffraction. This iron complex catalyzes the aziridination of electron-donating aryl azides and a wide variety of substituted aliphatic alkenes, including tetrasubstituted ones, in a "C(2) + N(1)" addition reaction. Finally, the catalyst can be recovered and reused up to three additional times without significant reduction in yield.