Chemo- and stereoselective CH oxidations and epoxidations/cis-dihydroxylations with H2O2, catalyzed by non-heme iron and manganese complexes

Manganese terpyridine artificial metalloenzymes for benzylic oxygenation and olefin epoxidation

New catalysts for non-directed hydrocarbon functionalization have great potential in organic synthesis. We hypothesized that incorporating a Mn-terpyridine cofactor into a protein scaffold would lead to artificial metalloenzymes (ArMs) in which the selectivity of the Mn cofactor could be controlled by the protein scaffold. We designed and synthesized a maleimide-substituted Mn-terpyridine cofactor and demonstrated that this cofactor could be incorporated into two different scaffold proteins to generate the desired ArMs. The structure and reactivity of one of these ArMs was explored, and the broad oxygenation capability of the Mn-terpyridine catalyst was maintained, providing a robust platform for optimization of ArMs for selective hydrocarbon functionalization.

Insights into the mechanistic and synthetic aspects of the Mo/P-catalyzed oxidation of N-heterocycles

A Mo/P catalytic system for an efficient gram-scale oxidation of a variety of nitrogen heterocycles to N-oxides with hydrogen peroxide as terminal oxidant has been investigated. Combined spectroscopic and crystallographic studies point to the tetranuclear Mo4P peroxo complex as one of the active catalytic species present in the solution. Based on this finding an optimized catalytic system has been developed. The utility and chemoselectivity of the catalytic system has been demonstrated by the synthesis of over 20 heterocyclic N-oxides.

Catalytic and mechanistic studies into the epoxidation of styrenes using manganese complexes of structurally similar polyamine ligands

The synthesis and catalytic activity of manganese(ii) complexes of two polyamine ligands is reported which highlights how a small structural change in the ligand affects the overall catalytic behaviour.

Mn(ii) acetate: an efficient and versatile oxidation catalyst for alcohols

A homogeneous catalytic system consisting of Mn(ii) acetate, tert-butylhydroperoxide, acetonitrile and trifluoroacetic acid oxidises various alcohols efficiently and selectively.

Manganese(ii) complexes of tetradentate 4N ligands with diazepane backbones for catalytic olefin epoxidation: effect of nucleophilicity of peroxo complexes on reactivity

Mononuclear Mn(ii) complexes of linear 4N ligands have been studied as catalysts for deformylation of aldehydes and epoxidation (H₂O₂) of unfunctionalised olefins to understand the role of ligand stereoelectronic factors.

Biomimetic oxidation of pyrene and related aromatic hydrocarbons. Unexpected electron accepting abilities of pyrenequinones

We present a mild catalytic method to oxidize PAHs and, in particular, pyrene, and we characterize the electron accepting abilities of pyrenequinones both in gas phase and in solution.

Asymmetric epoxidation with H2O2 by manipulating the electronic properties of non-heme iron catalysts

A non-heme iron complex that catalyzes highly enantioselective epoxidation of olefins with H2O2 is described. Improvement of enantiomeric excesses is attained by the use of catalytic amounts of carboxylic acid additives. Electronic effects imposed by the ligand on the iron center are shown to synergistically cooperate with catalytic amounts of carboxylic acids in promoting efficient O-O cleavage and creating highly chemo- and enantioselective epoxidizing species which provide a broad range of epoxides in synthetically valuable yields and short reaction times.

Chemoselective, iron(II)-catalyzed oxidation of a variety of secondary alcohols over primary alcohols utilizing H2O2 as the oxidant

A mild, iron-based catalyst system is presented that selectively oxidizes secondary alcohols to the corresponding hydroxy ketones in the presence of primary alcohols within 15 minutes at room temperature, utilizing H2O2 as the oxidant.

Recent catalytic approaches to chemical synthesis from carbon feedstocks

Traditional organic synthesis is driven by the need for functional molecules. The development of green chemical methods, however, is an increasingly important challenge in the context of global sustainability. To this end, the direct use of abundant carbon feedstocks in synthesis (such as CO, CO2, methanol, arenes, alkanes, α-olefins, and biological raw materials) aims to minimize waste production and increase efficiency.