Journal ArticleDOI
Asymmetric Epoxidations with H2O2 on Fe and Mn Aminopyridine Catalysts: Probing the Nature of Active Species by Combined Electron Paramagnetic Resonance and Enantioselectivity Study
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TLDR
In this article, electron paramagnetic resonance (EPR) spectroscopy and enantioselectivity studies were performed to identify the active oxygen-transferring species of the above systems, which can be identified as structurally similar oxometal(V) species of [((S,S)-pdp)MV═O(OCOR)]2+ (M = Fe, Mn; R = alkyl)Abstract:
Chiral bipyrrolidine based iron and manganese complexes [((S,S)-pdp)MII(OTf)2] catalyze the asymmetric epoxidation of various olefins with H2O2 in the presence of carboxylic acid additives with high efficiency (up to 1000 turnover number (TON)) and selectivity (up to 100%), and with good to high enantioselectivity (up to 93% enantiomeric excess (ee)) The enantioselectivity increases with growing steric demand of the acid On the basis of the electron paramagnetic resonance (EPR) spectroscopy and enantioselectivity studies, the active oxygen-transferring species of the above systems can be identified as structurally similar oxometal(V) species of the type [((S,S)-pdp)MV═O(OCOR)]2+ (M = Fe, Mn; R = alkyl)read more
Citations
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High-valent nonheme iron-oxo complexes: Synthesis, structure, and spectroscopy
Aidan R. McDonald,Lawrence Que +1 more
TL;DR: In this paper, a review of the great successes in iron-oxo chemistry over the past decade is presented, detailing various efforts to obtain ironoxo complexes in high yield, and to delve into their diverse structural and spectroscopic properties.
Journal ArticleDOI
Bioinspired Nonheme Iron Catalysts for C-H and C═C Bond Oxidation: Insights into the Nature of the Metal-Based Oxidants.
Williamson N. Oloo,Lawrence Que +1 more
TL;DR: These efforts to shed light on the nature of metastable peroxo intermediates are highlighted, which are trapped at -40 °C, in the reactions of the iron catalyst with H2O2 under various conditions and the high-valent species derived therefrom.
Journal ArticleDOI
Additive Effects on Asymmetric Catalysis
TL;DR: This review highlights a number of additives that can be used to make asymmetric reactions perfect, such as reduced reaction time, improved yield, or/and increased selectivity.
Journal ArticleDOI
Catalytic Asymmetric Oxygenations with the Environmentally Benign Oxidants H2O2 and O2.
TL;DR: An overview of catalyst systems capable of conducting asymmetric oxygenative transformations of organic molecules and, in line with the major trend to sustainability, relying on green oxidants H2O2 and O2 as the ultimate oxygen source is given.
References
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Journal ArticleDOI
Dioxygen activation at mononuclear nonheme iron active sites: enzymes, models, and intermediates.
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Direct C-H transformation via iron catalysis.
Journal ArticleDOI
Biologically inspired oxidation catalysis
Lawrence Que,William B. Tolman +1 more
TL;DR: The development of processes for selective hydrocarbon oxidation is a goal that has long been pursued, and extensive studies have revealed the key chemical principles that underlie their efficacy as catalysts for aerobic oxidations.
Journal ArticleDOI
A Predictably Selective Aliphatic C-H Oxidation Reaction for Complex Molecule Synthesis
Mark S. Chen,M. Christina White +1 more
TL;DR: An iron (Fe)–based small molecule catalyst that uses hydrogen peroxide (H2O2) to oxidize a broad range of substrates and Predictable selectivity is achieved solely on the basis of the electronic and steric properties of the C–H bonds, without the need for directing groups.
Journal ArticleDOI
Combined effects on selectivity in Fe-catalyzed methylene oxidation.
Mark S. Chen,M. Christina White +1 more
TL;DR: It is reported that an iron catalyst can achieve methylene C–H bond oxidations in diverse natural-product settings with predictable and high chemo-, site-, and even diastereoselectivities.
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