Development of a practical non-noble metal catalyst for hydrogenation of N-heteroarenes

Nature Catalysis, Год журнала: 2020, Номер 3(2), С. 135 - 142

Опубликована: Янв. 6, 2020

Язык: Английский

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Influence of solvent structure and hydrogen bonding on catalysis at solid–liquid interfaces

Chemical Society Reviews, Год журнала: 2021, Номер 50(22), С. 12308 - 12337

Опубликована: Янв. 1, 2021

A pedagogical review that deconvolutes the excess free energy effects of several solvent phenomena and connects findings across a variety catalytic reactions materials.

Язык: Английский

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Room temperature N-heterocyclic carbene manganese catalyzed selective N-alkylation of anilines with alcohols

Chemical Communications, Год журнала: 2019, Номер 55(44), С. 6213 - 6216

Опубликована: Янв. 1, 2019

The first example of room temperature non-noble metal homogeneous system catalyzed selective N-alkylation anilines with alcohols by a bis-NHC manganese complex is presented. This was applied to large range and anilines, including biologically relevant motifs challenging methanol. Experimental computational studies suggest an outer-sphere mechanism for this NHC-Mn system.

Язык: Английский

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Manganese‐Catalyzed Asymmetric Hydrogenation of Quinolines Enabled by π–π Interaction**

Angewandte Chemie International Edition, Год журнала: 2020, Номер 60(10), С. 5108 - 5113

Опубликована: Ноя. 26, 2020

Abstract The non‐noble metal‐catalyzed asymmetric hydrogenation of N‐heteroaromatics, quinolines, is reported. A new chiral pincer manganese catalyst showed outstanding catalytic activity in the affording high yields and enantioselectivities (up to 97 % ee). turnover number 3840 was reached at a low loading (S/C=4000), which competitive with most effective noble metal catalysts for this reaction. precise regulation enantioselectivity were ensured by π–π interaction.

Язык: Английский

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Enabling Two-Electron Pathways with Iron and Cobalt: From Ligand Design to Catalytic Applications

Journal of the American Chemical Society, Год журнала: 2019, Номер 141(23), С. 9106 - 9123

Опубликована: Май 14, 2019

Homogeneous catalysis with Earth-abundant, first-row transition metals, including iron and cobalt, has gained considerable recent attention as a potentially cost-effective sustainable alternative to more commonly historically used precious metals. Because fundamental organometallic transformations, such oxidative addition reductive elimination, are two-electron processes essential steps in many important catalytic cycles, controlling redox chemistry—in particular overcoming one-electron chemistry—has been central challenge Earth-abundant This Perspective focuses on approaches impart sufficiently strong ligand fields generate electron-rich metal complexes able promote reactions where the changes exclusively metal-based. Emphasis is placed how design exploration of chemistry coupled mechanistic understanding have discover catalysts for hydrogen isotope exchange pharmaceuticals cobalt C(sp2)–H borylation reactions. A pervasive theme that often unique from their precious-metal counterparts, demonstrating these elements offer host new opportunities reaction discovery catalysis.

Язык: Английский

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Mechanistic Studies of Hydride Transfer to Imines from a Highly Active and Chemoselective Manganate Catalyst

Journal of the American Chemical Society, Год журнала: 2019, Номер 141(29), С. 11677 - 11685

Опубликована: Июнь 28, 2019

We introduce a highly active and chemoselective manganese catalyst for the hydrogenation of imines. The has large scope, can reduce aldimines ketimines, tolerates variety functional groups, among them sensitive examples such as an olefin, ketone, nitriles, nitro aryl iodo substituent or benzyl ether. could investigate transfer step between imines hydride complex in detail. found that double deprotonation ligand is essential excess base does not lead to higher rate step. identified actual K–Mn-bimetallic species obtain structure K–Mn formed after by X-ray analysis. NMR experiments indicate well-defined reaction, which first order imine, bimetallic (K–Mn) hydride, independent from concentration potassium base. propose outer-sphere mechanism protons do seem be involved rate-determining step, leading transiently negatively charged nitrogen atom substrate reacts rapidly with HOtBu (2-methylpropan-2-ol) produce amine. This based on several observations, no dependency reaction concentration, observable amide complex, high constant conducted Hammett study. Furthermore, hydrogen catalytic cycle was experimentally probed monitored subsequent quantitative regeneration H2.

Язык: Английский

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Unmasking the Ligand Effect in Manganese-Catalyzed Hydrogenation: Mechanistic Insight and Catalytic Application

Journal of the American Chemical Society, Год журнала: 2019, Номер 141(43), С. 17337 - 17349

Опубликована: Окт. 21, 2019

Manganese-catalyzed hydrogenation reactions have attracted broad interest since the first report in 2016. Among reported catalytic systems, Mn catalysts supported by tridentate PNP- and NNP-pincer ligands most commonly been used. For example, a number of PNP-Mn pincer for aldehydes, aldimines, ketones, nitriles, esters. Furthermore, various NNP-Mn shown to be active less-reactive substrates such as amides, carbonates, carbamates, urea derivations. These observations indicated that exhibit higher reactivity than their PNP counterparts. Such ligand effect Mn-catalyzed has yet confirmed. Herein, we investigated origin applicability this effect. A combination experimental theoretical investigations showed on complexes were more electron-rich less sterically hindered counterparts, leading series reactions. Inspired hydrogenations, developed N-heterocycles. Specifically, hydrogenated N-heterocycles (32 examples) with up 99% yields, corresponding afforded low under same conditions. This verified is generally applicable both carbonyl noncarbonyl based catalysis.

Язык: Английский

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Manganese Catalyzed Hydrogenation of Carbamates and Urea Derivatives

Journal of the American Chemical Society, Год журнала: 2019, Номер 141(33), С. 12962 - 12966

Опубликована: Июль 31, 2019

We report the hydrogenation of carbamates and urea derivatives, two most challenging carbonyl compounds to be hydrogenated, catalyzed for first time by a complex an earth-abundant metal. The reaction these CO2-derived compounds, manganese pincer complex, yields methanol in addition amine alcohol, which makes this methodology sustainable alternative route conversion CO2 methanol, involving base-metal catalyst. Moreover, proceeds under mild pressure (20 bar). Our observations support mechanism Mn–H complex. A plausible catalytic cycle is proposed based on informative mechanistic experiments.

Язык: Английский

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Manganese(I)‐Catalyzed β‐Methylation of Alcohols Using Methanol as C₁ Source

Angewandte Chemie International Edition, Год журнала: 2019, Номер 59(1), С. 215 - 220

Опубликована: Окт. 25, 2019

Highly selective β-methylation of alcohols was achieved using an earth-abundant first row transition metal in the air stable molecular manganese complex [Mn(CO)

Язык: Английский

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Dehydrogenative Synthesis of Quinolines, 2-Aminoquinolines, and Quinazolines Using Singlet Diradical Ni(II)-Catalysts

The Journal of Organic Chemistry, Год журнала: 2019, Номер 84(5), С. 2626 - 2641

Опубликована: Янв. 28, 2019

Simple, straightforward, and atom economic methods for the synthesis of quinolines, 2-aminoquinolines, quinazolines via biomimetic dehydrogenative condensation/coupling reactions, catalyzed by well-defined inexpensive easy to prepare singlet diradical Ni(II)-catalysts featuring two antiferromagnetically coupled diamine type ligands are described. Various polysubstituted were synthesized in moderate good yields from different low-cost readily accessible starting materials. Several control experiments carried out get insight into reaction mechanism which shows that nickel coordinated participate a synergistic way during dehydrogenation alcohols.

Язык: Английский

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