Examination of a dicationic rhodium methyl aquo complex

Manbeck, Kimberly A.; Brennessel, William W.; Jones, William D.

doi:10.1016/j.ica.2012.12.002

Cited by 8 publications

(7 citation statements)

References 27 publications

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“…195 Jones and co-workers found that the cationic rhodium− bipyridine complex underwent C−H activation at the bipyridine C3 position to afford the "rollover" cyclometalated bipyridine complex (Scheme 60). 196 Inspired by this work, Lu and co-workers discovered that the [RhCp*Cl 2 ] 2 species could activate the C(sp 2 )−H bond of 2phenylpyridine (ppy) in water (Scheme 61). 197,198 Control studies of rhodacycle formation (99% in water vs 0% in DCE) suggested the vital role of water in the C−H activation step.…”

Section: Metal-based Catalystsmentioning

confidence: 99%

Catalytic Organic Reactions in Water toward Sustainable Society

et al. 2017

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Traditional organic synthesis relies heavily on organic solvents for a multitude of tasks, including dissolving the components and facilitating chemical reactions, because many reagents and reactive species are incompatible or immiscible with water. Given that they are used in vast quantities as compared to reactants, solvents have been the focus of environmental concerns. Along with reducing the environmental impact of organic synthesis, the use of water as a reaction medium also benefits chemical processes by simplifying operations, allowing mild reaction conditions, and sometimes delivering unforeseen reactivities and selectivities. After the "watershed" in organic synthesis revealed the importance of water, the development of water-compatible catalysts has flourished, triggering a quantum leap in water-centered organic synthesis. Given that organic compounds are typically practically insoluble in water, simple extractive workup can readily separate a water-soluble homogeneous catalyst as an aqueous solution from a product that is soluble in organic solvents. In contrast, the use of heterogeneous catalysts facilitates catalyst recycling by allowing simple centrifugation and filtration methods to be used. This Review addresses advances over the past decade in catalytic reactions using water as a reaction medium.

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Section: Metal-based Catalystsmentioning

confidence: 99%

Catalytic Organic Reactions in Water toward Sustainable Society

et al. 2017

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“…We recently reported mono-C–H amidation “on water” with tert -butyl 2,4-dinitrophenoxycarbamate as an electron-deficient nitrene source, and Jones reported the “rollover” metalation of bipyridine rings of rhodium complexes through C–H activation with water as solvent . Inspired by these studies, , we herein report water promoted rhodium-catalyzed direct amination of arenes with a variety of aryl azides having both electron-donating and -withdrawing substituents (Scheme b). As the starting materials, catalyst, and additive are not particularly soluble in water, the reactions are conducted “on water” .…”

mentioning

confidence: 92%

“…Due to the low stability of metal catalysts and ligands in water, direct metal catalyzed C–H amination in or on water has been developed minimally although C–H functionalization in/on water has significant importance . We recently reported mono-C–H amidation “on water” with tert -butyl 2,4-dinitrophenoxycarbamate as an electron-deficient nitrene source, and Jones reported the “rollover” metalation of bipyridine rings of rhodium complexes through C–H activation with water as solvent . Inspired by these studies, , we herein report water promoted rhodium-catalyzed direct amination of arenes with a variety of aryl azides having both electron-donating and -withdrawing substituents (Scheme b).…”

mentioning

confidence: 99%

Rhodium-Catalyzed Selective Mono- and Diamination of Arenes with Single Directing Site “On Water”

Ali

Yao

et al. 2016

Org. Lett.

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A Rh(III)-catalyzed selective C-H amination of 2-phenylpyridine derivatives is reported. With pyridine as a directing group, the reaction has high mono- or diamination selectivity, and a wide range of effective substrates, including electron-deficient and -rich aryl azides. Water helps to promote C-H activation, and the concept of a water promoted rollover mechanism is postulated for the diamination step. The reactions were conducted using a Schlenk flask and proceeded smoothly "on water" under atmospheric conditions with nitrogen gas as the only byproduct.

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“…16,17 However, developing a Rh-based catalyst presents some challenges. 18,19 A key step in the functionalization of hydrocarbons by Shilov-based Pt catalysts is the reductive elimination (RE) of MeX (X = halide or pseudo-halide: Cl − , CF 3 CO 2 − , HSO 4 − , OH − , etc.) from a X-Pt(IV)-CH 3 intermediate (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

Reductive functionalization of a rhodium(iii)–methyl bond by electronic modification of the supporting ligand

et al. 2014

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Net reductive elimination (RE) of MeX (X = halide or pseudo-halide: Cl(-), CF3CO2(-), HSO4(-), OH(-)) is an important step during Pt-catalyzed hydrocarbon functionalization. Developing Rh(I/III)-based catalysts for alkane functionalization is an attractive alternative to Pt-based systems, but very few examples of RE of alkyl halides and/or pseudo-halides from Rh(III) complexes have been reported. Here, we compare the influence of the ligand donor strength on the thermodynamic potentials for oxidative addition and reductive functionalization using [(t)Bu3terpy]RhCl (1) {(t)Bu3terpy = 4,4',4''-tri-tert-butylpyridine} and [(NO2)3terpy]RhCl (2) {(NO2)3terpy = 4,4',4''-trinitroterpyridine}. Complex 1 oxidatively adds MeX {X = I(-), Cl(-), CF3CO2(-) (TFA(-))} to afford [(t)Bu3terpy]RhMe(Cl)(X) {X = I(-) (3), Cl(-) (4), TFA(-) (5)}. By having three electron-withdrawing NO2 groups, complex 2 does not react with MeCl or MeTFA, but reacts with MeI to yield [(NO2)3terpy]RhMe(Cl)(I) (6). Heating 6 expels MeCl along with a small quantity of MeI. Repeating this experiment but with excess [Bu4N]Cl exclusively yields MeCl, while adding [Bu4N]TFA yields a mixture of MeTFA and MeCl. In contrast, 3 does not reductively eliminate MeX under similar conditions. DFT calculations successfully predict the reaction outcome by complexes 1 and 2. Calorimetric measurements of [(t)Bu3terpy]RhI (7) and [(t)Bu3terpy]RhMe(I)2 (8) were used to corroborate computational models. Finally, the mechanism of MeCl RE from 6 was investigated via DFT calculations, which supports a nucleophilic attack by either I(-) or Cl(-) on the Rh-CH3 bond of a five-coordinate Rh complex.

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Examination of a dicationic rhodium methyl aquo complex

Cited by 8 publications

References 27 publications

Catalytic Organic Reactions in Water toward Sustainable Society

Catalytic Organic Reactions in Water toward Sustainable Society

Rhodium-Catalyzed Selective Mono- and Diamination of Arenes with Single Directing Site “On Water”

Reductive functionalization of a rhodium(iii)–methyl bond by electronic modification of the supporting ligand

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