Biomimetic Iron‐Catalyzed Asymmetric Epoxidations: Fundamental Concepts, Challenges and Opportunities

Abstract

The state-of-the-art in the non-enzymatic iron-catalyzed asymmetric epoxidation of C=C double bonds is reviewed within the broader context of biomimetic oxidation catalysis. After introducing fundamental concepts of oxygen activation in nature and by man, historical landmarks, recent breakthroughs, scopes and limitations in relation to existing methodologies and their impact on future directions are assessed, focusing mainly on progress made in the last five years.

Biologically inspired non-heme iron-catalysts for asymmetric epoxidation; design principles and perspectives

“…In enzymes, the use of O 2 , a four electron oxidant, to perform two electron oxidation reactions such as monoxygenations requires a very precise controlled injection of protons and electrons either from an electron transport chain or from a co-substrate. [23][24][25][26][27][28][29][30][31][32][33][34][35][36] The delivery of an oxygen atom in a stereoselective manner constitutes a remarkable accomplishment in the frame of biologically inspired catalysis, because it requires exquisite control over the nature of the oxidant, calling for fine control of the mechanism of O-O activation (presumably via its lysis) when peroxides are employed. Among these, complexes that can catalytically utilise H 2 O 2 to oxidize organic substrates constitute the most interesting cases because of the benign nature of this oxidant.…”

Asymmetric Epoxidation of α,β‐Unsaturated Ketones Catalyzed by Chiral Iron Complexes of (R,R)‐3,4‐Diaminopyrrolidine Derived N4‐Ligands with Camphorsulfonyl Sidearms

“…Therefore, iron‐based catalysts have received increasing attention in catalytic enantioselective epoxidation. Based on the structure of the non‐heme ferritase active center, a variety of iron complex‐based chiral catalysts were designed and synthesized to catalyze the asymmetric epoxidation of olefins with environmentally friendly hydrogen peroxide …”

“…Based on the structure of the non-heme ferritase active center, a variety of iron complexbased chiral catalysts were designed and synthesized to catalyze the asymmetric epoxidation of olefins with environmentally friendly hydrogen peroxide. [13][14][15] The first iron-based catalyst, which was used to simulate the activity center of non-heme iron-based enzymes in asymmetric epoxidation, is a dinuclear complex formed by the coordination of a bipyridyl ligand of a terpene and two ferrous chloride molecules. The complex catalyzes the asymmetric epoxidation of styrenes with hydrogen peroxide, and the desired products were obtained in good yields with modest enantioselectivities.…”

“…) 13. C NMR (100 MHz, CDCl 3 , TMS), δ(ppm): 21.77, 28.32, 48.92, 49.48, 79.35, 80.44, 128.05, 128.11, 130.…”

Epoxidation of strained alkenes catalysed by (1,2-dimethyl-4(1H)pyridinone-3-olate)2MnIIICl

“…6 Two of the most noticeable achievements are probably the characterisation of the Fe(IV/V)=O active species and the identification of subtle effects of ligand structure and reaction conditions on the reactivity (e.g. epoxidation vs cis-dihydroxylation competition).…”