Comparative Nitrene-Transfer Chemistry to Olefins Mediated by First-Row Transition Metal Catalysts Supported by a Pyridinophane Macrocycle with N4 Ligation.

A 12-membered pyridinophane scaffold containing two pyridine and two tertiary amine residues is examined as a prototype ligand (N4) for supporting nitrene transfer to olefins. The known [(N4)M(MeCN)] (M = Mn, Fe, Co, and Ni) and [(N4)Cu(MeCN)] cations are synthesized with the hexafluorophosphate counteranion. The aziridination of para-substituted styrenes with PhI=NTs (Ts = tosyl) in various solvents proved to be high yielding for the Cu(I) and Cu(II) reagents, in contrast to the modest efficacy of all other metals.