Highly Selective and Catalytic Oxygenations of C−H and C=C Bonds by a Mononuclear Nonheme High‐Spin Iron(III)‐Alkylperoxo Species

Abstract

Abstract The reactivity of a mononuclear high‐spin iron(III)‐alkylperoxo intermediate [Fe III ( t ‐BuL Urea )(OOCm)(OH 2 )] 2+ ( 2 ), generated from [Fe II ( t ‐BuL Urea )(H 2 O)(OTf)](OTf) ( 1 ) [ t ‐BuL Urea =1,1′‐(((pyridin‐2‐ylmethyl)azanediyl)bis(ethane‐2,1‐diyl))bis(3‐(tert‐butyl)urea), OTf=trifluoromethanesulfonate] with cumyl hydroperoxide (CmOOH), toward the C−H and C=C bonds of hydrocarbons is reported. 2 oxygenates the strong C−H bonds of aliphatic substrates with high chemo‐ and stereoselectivity in the presence of 2,6‐lutidine. While 2 itself is a sluggish oxidant, 2,6‐lutidine assists the heterolytic O−O bond cleavage of the metal‐bound alkylperoxo, giving rise to a reactive metal‐based oxidant. The roles of the urea groups on the supporting ligand, and of the base, in directing the selective and catalytic oxygenation of hydrocarbon substrates by 2 are discussed.