Catalytic replacement of unactivated alkane carbon-hydrogen bonds with carbon-X bonds (X = nitrogen, oxygen, chlorine, bromine, or iodine). Coupling of intermolecular hydrocarbon activation by MnIIITPPX complexes with phase-transfer catalysis

Hill, Craig L.; Smegal, John A.; Henly, Timothy J.

doi:10.1021/jo00167a023

Cited by 78 publications

(23 citation statements)

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“…The M d~ -0 p~ MOS are obviously important in alkane hydroxylation since it is these MOS which are responsible for placing unpaired electron density on the 0. These and other differences exist, but our working thesis is that the changes in reactivity are intimately linked to the energy of the metal u MO. The nature of the oxygen atom in the ferry1 state of P-450, and its model complexes, has been the subject of much speculation [1][2][3][4][5]271. The chemical character of the 0 is neither highly electrophilic nor highly nucleophilic, but it lies in a region in between these two extremes; the exact nature of the 0 atom depends on the metal, axial ligand or porphyrin ring.…”

Section: Discussionmentioning

confidence: 99%

“…Fourth, the topology and trends among similar reactions are expected to be well reproduced. The final, and most important, justification for using the INDO/ 1 method is that experimental data [1][2][3]6,7, for alkane hydroxylation is available with which to compare the theoretical results. Construction of the potential surface for hydroxylation.…”

Section: Initial Substrate/oxidant Interactionmentioning

confidence: 99%

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Alkane hydroxylations

Cundari

Drago

1990

Int. J. Quantum Chem.

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The INDO/ 1 semi-empirical method is used to analyze the hydroxylation of alkanes by models for the putative active species in cytochromes P-450. In the insertion of oxygen into the C-H bond by a M -0 complex there are four atoms of particular interest, the metal and oxygen atoms of the oxidant plus the C and H atom of the C-H bond to be activated. With four atoms being studied (3N-6=), 6 degrees of freedom need to he described and a nearly intractable computational problem results. Thus, two reaction coordinates (CHI and OAT ) were developed in an attempt to describe alkane hydroxylation in a chemically meaningful way. CHI (C-H insertion) is a measure of the extent to which the C-H bond has been activated and transferred to the 0 atom. OAT (oxygen atom transfer) is a measure of the extent to which the C -0 bond in the alcohol product has formed. The models chosen for the present study are manganyl (MnO) and fenyl (FeO) porphyrin complexes. Experimental evidence for manganese prophyrin complexes shows that as the axial ligand is made a stronger donor the insertion of the 0 atom into the C-H bond becomes less concerted. The INDO/ 1 method was used to calculate the points on the PES determined by the changes in OAT and CHI. The results point to the axial ligand modifying the pathway by changing the relative electro-/nucleophilicity of the oxygen atom.

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Section: Discussionmentioning

confidence: 99%

Section: Initial Substrate/oxidant Interactionmentioning

confidence: 99%

Alkane hydroxylations

Cundari

Drago

1990

Int. J. Quantum Chem.

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“…[28,29] However, these reports remained unexploited for almost thirty years as establishing control for halogenation over oxygenation was not possible. [28,29] However, these reports remained unexploited for almost thirty years as establishing control for halogenation over oxygenation was not possible.…”

Section: Carbon-halogen Bond Formation By C-h Activationmentioning

confidence: 99%

Recent Advances of Manganese Catalysis for Organic Synthesis

2016

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Manganese is a non‐toxic, inexpensive and earth abundant metal, so is a perfect candidate for catalysis whether as a replacement for precious metals or in the search for novel reactivity. Despite this, manganese catalysis has not undergone the same development of other earth‐abundant metals (particularly iron and cobalt). This review details recent synthetic methodologies using manganese catalysts, including C–H activation, late stage fluorination, hydrosilylation and cross‐coupling.

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“…83–85 The key idea is that the reactive species are confined to a small interphase zone or are transported with a phase‐transfer catalyst. 86 Because the products are of much lower concentration in the reactive region, unselective overfunctionalization is much less likely. 87…”

Section: Organocatalysis: Phase‐transfer Halogenations (Western Quadrmentioning

confidence: 99%

Selective alkane CH‐bond functionalizations utilizing oxidative single‐electron transfer and organocatalysis

Schreiner

Fokin

2004

The Chemical Record

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Alkane C-H-bond functionalization methods not utilizing metal-catalysis are discussed based on experimental and computational data, beginning with molecule-induced homolysis (reactions of alkanes with dioxiranes). Electrophilic reactions are elaborated next with an emphasis on mechanistic details that reveal that many so-called electrophilic C-H or C-C-bond insertions can be rationalized by electron-transfer reactions (inner sphere, H-coupled, and outer sphere). Finally, radical functionalizations utilizing carbon-centered (relatively stable) radicals generated under organocatalytic (phase-transfer catalysis, PTC) conditions are presented as valuable alternatives to other radical-chain alkane functionalizations. The remarkable chemo- and regioselectivities of these PTC radical reactions and the tolerance of high strain in certain aliphatic hydrocarbons make them particularly useful for laboratory-scale halogenations, in particular, iodinations of unactivated alkane C-H-bonds.

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Catalytic replacement of unactivated alkane carbon-hydrogen bonds with carbon-X bonds (X = nitrogen, oxygen, chlorine, bromine, or iodine). Coupling of intermolecular hydrocarbon activation by MnIIITPPX complexes with phase-transfer catalysis

Abstract: Cyclohexan (I) reagiert mit Iodosobenzol (II) in Gegenwart von Mangan(III)‐tetraphenylporphyrin‐Komplexen (III), die die C‐H‐Bindung aktivieren, in wäßrigem Milieu und in Gegenwart von verschiedenen Anionen X‐ zu Gemischen der Reaktionsprodukte (IV)‐(VI).

Cited by 78 publications

References 0 publications

Alkane hydroxylations

Alkane hydroxylations

Recent Advances of Manganese Catalysis for Organic Synthesis

Selective alkane CH‐bond functionalizations utilizing oxidative single‐electron transfer and organocatalysis

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