Oxidation of activated methylene groups to ketones catalyzed by new iron phosphinooxazoline complexes and by iron(II) triflate

Lenze, Matthew; Bauer, Eike B.

doi:10.1016/j.molcata.2009.05.002

Cited by 23 publications

(10 citation statements)

References 50 publications

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“…On the other hand, the mononuclear iron complexes carrying two tridentate oxazoline ligands of type 56a or the structurally closely related, phosphine containing ligands 56b-56d, exhibit only modest reactivity in the oxidation of benzylic C−H bonds with H2O2 or tBHP respectively. 131,132 Antunes and co-workers reported a series of tri-and tetradentate ligands of type 57a-57d ( Figure 10). [133][134][135] The corresponding iron complexes catalyse the oxidation of cyclohexane with H2O2 and mainly produce cyclohexanol and cyclohexanone.…”

Section: Iron Nonheme Complexes Bearing C- O-and S-donor Ligandsmentioning

confidence: 99%

Molecular iron complexes as catalysts for selective C–H bond oxygenation reactions

2015

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The selective oxygenation of C-H bonds is a promising and interesting task for both academia and chemical industry. Inspired by the efficiency and selectivity of naturally occurring enzymes, iron heme and nonheme complexes have proven to be valuable candidates for the development of environmentally friendly catalysts as alternative to traditional systems. This feature article summarises developments of the last decade regarding oxygenation reactions of aliphatic and aromatic substrates with various oxidants catalysed by molecular iron complexes. With a special focus on the catalytic performance of the systems, both the potential and the limitations as well as mechanistic aspects are discussed in some detail.

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Section: Iron Nonheme Complexes Bearing C- O-and S-donor Ligandsmentioning

confidence: 99%

Molecular iron complexes as catalysts for selective C–H bond oxygenation reactions

2015

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“…Mechanistic studies clarifying the nature of the catalytically active iron species19e,51,52 as well as the roles of the N , O ‐acetal/iminium ion equilibrium and the HP(O)(OR) 2 /P(OH)(OR) 2 tautomerism are in progress.…”

Section: Discussionmentioning

confidence: 99%

NOC Chemistry for Tuberculosis—Further Investigations on the Structure–Activity Relationships of Antitubercular Isoxazole‐3‐carboxylic Acid Ester Derivatives

et al. 2010

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The dehydrogenative α‐phosphonation of substituted N,N‐dialkylanilines by dialkyl H‐phosphonates was achieved under mild conditions by using environmentally benign iron(II) chloride as catalyst and tert‐butyl hydroperoxide as oxidant. The reaction proceeded in the presence of electron‐donating (methoxy, methyl, benzyl) and electron‐withdrawing ring‐substitutents (bromo, carbonyl, carboxyl, m‐nitro) in moderate to good yields. The X‐ray crystal structure of N‐(5,5‐dimethyl‐2‐oxo‐2λ5‐[1,3,2]dioxaphosphinan‐2‐yl‐methyl)‐N‐methyl‐p‐toluidine was determined. Bis‐(4‐(dimethylamino)phenyl)methane and bis‐4,4′‐(dimethylamino)benzophenone underwent bisphosphonation selectively by respective monophosphonation at the remote dimethylamino groups. Furthermore, the use of excess dialkyl H‐phosphonate and oxidant allowed us to functionalize both methyl groups of N(CH3)2 in N,N‐dimethyl‐p‐toluidine and N,N‐dimethylaminomesidine, respectively, to obtain α,α′‐bisphosphonatoamines in high yield.

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“…Thus, an impressive number of papers has appeared in the literature, concerning the design and properties of various iron catalysts, most of which bear nitrogen chelating ligands, mimicking the active sites of redox iron-based enzymes (Engelmann et al, 2016;Oszajca et al, 2016;Sahu and Goldberg, 2016). Although, also a moderate number of ligand-bearing donor atoms other than nitrogen have been successfully employed in association to iron for oxidation reactions (Lenze and Bauer, 2009;Rani and Bhat, 2010;Farnetti et al, 2020), however such complexes generally show inferior catalytic properties in comparison to bioinspired iron derivatives with nitrogen ligands. In this view, much effort has been spent in the synthesis of novel nitrogen ligands which might tune the iron oxidation properties.…”

Section: Introductionmentioning

confidence: 99%

Iron-Catalyzed Oxidation of 1-Phenylethanol and Glycerol With Hydrogen Peroxide in Water Medium: Effect of the Nitrogen Ligand on Catalytic Activity and Selectivity

Ros

Gianferrara

Crotti³

et al. 2020

Front. Chem.

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The iron(II) complexes [Fe(bpy) 3 ](OTf) 2 (bpy = 2,2'-bipyridine; OTf = CF 3 SO 3) (1) and [Fe(bpydeg) 3 ](OTf) 2 (bpydeg = N 4 ,N 4-bis(2-(2-methoxyethoxy)ethyl) [2,2'-bipyridine]-4,4'-dicarboxamide) (2), the latter being a newly synthesized ligand, were employed as catalyst precursors for the oxidation of 1-phenylethanol with hydrogen peroxide in water, using either microwave or conventional heating. With the same oxidant and medium the oxidation of glycerol was also explored in the presence of 1 and 2, as well as of two similar iron(II) complexes bearing tridentate ligands, i.e., [Fe(terpy) 2 ](OTf) 2 (terpy = 2, 6-di(2-pyridyl)pyridine) (3) and [Fe(bpa) 2 ](OTf) 2 (bpa = bis(2-pyridinylmethyl)amine) (4): in most reactions the major product formed was formic acid, although with careful tuning of the experimental conditions significant amounts of dihydroxyacetone were obtained. Addition of heterocyclic amino acids (e.g., picolinic acid) increased the reaction yields of most catalytic reactions. The effect of such additives on the evolution of the catalyst precursors was studied by spectroscopic (NMR, UV-visible) and ESI-MS techniques.

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Oxidation of activated methylene groups to ketones catalyzed by new iron phosphinooxazoline complexes and by iron(II) triflate

Cited by 23 publications

References 50 publications

Molecular iron complexes as catalysts for selective C–H bond oxygenation reactions

Molecular iron complexes as catalysts for selective C–H bond oxygenation reactions

NOC Chemistry for Tuberculosis—Further Investigations on the Structure–Activity Relationships of Antitubercular Isoxazole‐3‐carboxylic Acid Ester Derivatives

Iron-Catalyzed Oxidation of 1-Phenylethanol and Glycerol With Hydrogen Peroxide in Water Medium: Effect of the Nitrogen Ligand on Catalytic Activity and Selectivity

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