Manganese-catalyzed hydrogenation, dehydrogenation, and hydroelementation reactions

Chemical Society Reviews, Год журнала: 2022, Номер 51(11), С. 4386 - 4464

Опубликована: Янв. 1, 2022

The emerging field of organometallic catalysis has shifted towards research on Earth-abundant transition metals due to their ready availability, economic advantage, and novel properties. In this case, manganese, the third most abundant transition-metal in Earth's crust, emerged as one leading competitors. Accordingly, a large number molecularly-defined Mn-complexes been synthesized employed for hydrogenation, dehydrogenation, hydroelementation reactions. regard, catalyst design is based three pillars, namely, metal-ligand bifunctionality, ligand hemilability, redox activity. Indeed, developed catalysts not only differ chelating atoms they possess but also working principles, thereby different turnover numbers product molecules. Hence, critical assessment molecularly defined manganese terms atoms, reaction conditions, mechanistic pathway, significant. Herein, we analyze complexes catalytic activity, versatility allow multiple transformations routes convert substrates target This article will be helpful get significant insight into design, aiding design.

Язык: Английский

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Catalytic asymmetric silicon-carbon bond-forming transformations based on Si-H functionalization

Science China Chemistry, Год журнала: 2023, Номер 66(6), С. 1654 - 1687

Опубликована: Май 4, 2023

Язык: Английский

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Manganese-Catalyzed Dehydrogenative Synthesis of Urea Derivatives and Polyureas

ACS Catalysis, Год журнала: 2022, Номер 12(12), С. 6923 - 6933

Опубликована: Май 27, 2022

Urea derivatives have significant applications in the synthesis of resin precursors, dyes, agrochemicals, and pharmaceutical drugs. Furthermore, polyureas are useful plastics with coating, adhesive, biomedical industries. However, conventional methods for urea involve toxic reagents such as (di)isocyanates, phosgene, CO, azides. We present here (poly)ureas using much less reagents─(di)amines methanol─via a catalytic dehydrogenative coupling process. The reaction is catalyzed by pincer complex an earth-abundant metal, manganese, liberates H2 gas, valuable itself, only byproduct, making overall process highly atom-economic. A broad variety symmetrical unsymmetrical been synthesized moderate to quantitative yields this protocol. Mechanistic insights also provided experiments DFT computation, suggesting that proceeds via isocyanate intermediate.

Язык: Английский

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E-Selective Manganese-Catalyzed Semihydrogenation of Alkynes with H₂ Directly Employed or In Situ-Generated

ACS Catalysis, Год журнала: 2022, Номер 12(4), С. 2253 - 2260

Опубликована: Янв. 31, 2022

Selective semihydrogenation of alkynes with the Mn(I) alkyl catalyst fac-[Mn(dippe)(CO)3(CH2CH2CH3)] (dippe = 1,2-bis(di-iso-propylphosphino)ethane) as a precatalyst is described. The required hydrogen gas either directly employed or in situ-generated upon alcoholysis KBH4 methanol. A series aryl-aryl, aryl-alkyl, alkyl-alkyl, and terminal was readily hydrogenated to yield E-alkenes good excellent isolated yields. reaction proceeds at 60 °C for 60-90 loadings 0.5-2 mol %. implemented protocol tolerates variety electron-donating electron-withdrawing functional groups, including halides, phenols, nitriles, unprotected amines, heterocycles. can be upscaled gram scale. Mechanistic investigations, deuterium-labeling studies density theory (DFT) calculations, were undertaken provide reasonable mechanism, showing that initially formed Z-isomer undergoes fast isomerization afford thermodynamically more stable E-isomer.

Язык: Английский

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Manganese Alkyl Carbonyl Complexes: From Iconic Stoichiometric Textbook Reactions to Catalytic Applications

Accounts of Chemical Research, Год журнала: 2022, Номер 55(18), С. 2740 - 2751

Опубликована: Сен. 8, 2022

ConspectusThe activation of weakly polarized bonds represents a challenging, yet highly valuable process. In this context, precious metal catalysts have been used as reliable compounds for the rather inert last several decades. Nevertheless, base-metal complexes including cobalt, iron, or nickel are currently promising candidates substitution noble metals in order to develop more sustainable processes. past few years, manganese(I)-based were heavily employed efficient (de)hydrogenation reactions. However, vast majority these operate via metal–ligand bifunctionality already well implemented decades ago. Although high reactivity can be achieved various reactions, concept is often not applicable certain transformations due outer-sphere mechanisms. Account, we outline potential alkylated Mn(I)-carbonyl nonpolar and moderately polar E–H (E = H, B, C, Si) disclose our successful approach utilization field homogeneous catalysis. This involves rational design manganese hydrogenation reactions involving ketones, nitriles, carbon dioxide, alkynes. addition that, reduction alkenes by dihydrogen could series well-defined which was possible before. Furthermore, elucidate Mn-based hydrofunctionalization carbon–carbon multiple bonds. Our investigations unveiled novel insights into reaction pathways dehydrogenative silylation trans-1,2-diboration terminal alkynes, reported transition metals. Due catalyst design, under mild conditions. Delightfully, all bench-stable compounds. We took advantage fact that Mn(I) alkyl known undergo migratory insertion group CO ligand, yielding an unsaturated acyl intermediate. Hydrogen atom abstraction ligand then paves way active species variety catalytic proceed inner-sphere textbook well-known decades, application still its infancy. A brief historical overview manganese(I)–carbonyl provided, covering synthesis especially iconic stoichiometric transformations, e.g., carbonylation, intensively examined Calderazzo, Moss, others. An future applications defined will given, may inspire researchers development (base-)metal catalysts.

Язык: Английский

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Synthesis of functionalized phosphorus-containing tetraorganosilanes

Russian Chemical Bulletin, Год журнала: 2023, Номер 72(3), С. 715 - 723

Опубликована: Март 1, 2023

Язык: Английский

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Hydroboration of Terminal Alkenes and trans‐1,2‐Diboration of Terminal Alkynes Catalyzed by a Manganese(I) Alkyl Complex

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(46), С. 24488 - 24492

Опубликована: Авг. 26, 2021

A MnI -catalyzed hydroboration of terminal alkenes and a 1,2-diboration alkynes with pinacolborane (HBPin) is described. For alkenes, anti-Markovnikov takes place; for the reaction proceeds excellent trans-1,2-selectivity. The most active pre-catalyst bench-stable alkyl bisphosphine complex fac-[Mn(dippe)(CO)3 (CH2 CH2 CH3 )]. catalytic process initiated by migratory insertion CO ligand into Mn-alkyl bond to yield an acyl intermediate, which undergoes B-H cleavage HBPin (for alkenes) rapid C-H alkynes), forming boryl acetylide catalysts [Mn(dippe)(CO)2 (BPin)] (C≡CR)], respectively. broad variety aromatic aliphatic was efficiently selectively borylated. Mechanistic insights are provided based on experimental data DFT calculations revealing that acceptorless operating involving dihydrogen release.

Язык: Английский

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A Phosphine-Oxide Cobalt(II) Complex and Its Catalytic Activity Studies toward Alcohol Dehydrogenation Triggered Direct Synthesis of Imines and Quinolines

Inorganic Chemistry, Год журнала: 2024, Номер 63(21), С. 9786 - 9800

Опубликована: Май 13, 2024

Herein, a new pincer-like amino phosphine donor ligand, H2L1, and its phosphine-oxide analog, H2L2, were synthesized. Subsequently, cobalt(II) complexes 1 2 synthesized by the reaction of anhydrous Co(II)Cl2 with ligands H2L1 respectively. The fully characterized various physicochemical spectroscopic characterization techniques. Finally, identity was confirmed single crystal X-ray structure determination. ligand containing complex converted to oxide in air acetonitrile solution. Both investigated as precatalysts for alcohol dehydrogenation-triggered synthesis imines air. more efficient than 1. A wide array alcohols amines successfully reacted mild condition result good excellent yields. Precatalyst also highly varieties quinolines As H2L2 has side arms that can be deprotonated, we base (KOtBu) promoted deprotonation events studies DFT calculations. These have shown mono amine arm attached pyridine is quite feasible, leads dearomatized pyridyl ring 2a. mechanistic investigations catalytic reaction, combination experimental computational studies, suggested complex, 2a acted an active catalyst. proceeded through hydride transfer pathway. activation barrier this step calculated 26.5 kcal/mol, which consistent temperature under aerobic conditions. Although are explored such reactions, ligand-containing still unexplored.

Язык: Английский

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Nickel-Catalyzed Ring-Opening of Benzofurans for the Divergent Synthesis of ortho-Functionalized Phenol Derivatives

ACS Catalysis, Год журнала: 2023, Номер 13(4), С. 2432 - 2442

Опубликована: Фев. 2, 2023

The ring-opening reaction of benzofuran is a highly desirable, yet underdeveloped transformation for the construction valuable phenol derivatives. Herein, we report nickel-catalyzed with silanes, giving ortho-alkene-, branched/linear alkyl silane-, and alkenyl silane-substituted derivatives selectively. Control experiments DFT calculations supported Ni–H insertion β–O elimination to achieve formal C–O bond activation but not through direct oxidative addition nickel (0) into benzofurans. Further regioselective hydrosilylation or dehydrogenative silylation occurs via Ni(I)–H Ni(I)–[Si] intermediates form ortho-branched/linear silane-

Язык: Английский

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Cobalt-catalyzed dehydrogenative cross-coupling reaction: Selective access to dihydrosiloxanes, hydrosiloxanes and functionalized silsesquioxanes

Journal of Catalysis, Год журнала: 2023, Номер 423, С. 1 - 9

Опубликована: Апрель 27, 2023

Disclosed is a mild, scalable, and chemoselective cross-dehydrogenative functionalization protocol for the construction of Si−O−Si moieties under cobalt catalysis. The reaction has broad scope can be used to synthesize wide range silicon building blocks, including challenging dihydrosiloxanes functionalized silsesquioxanes. Most importantly, results are placed into context by benchmarking with state-of-the-art methods. Remarkably, utilized PNP-Co catalyst enables development further synthetic strategies such as one-pot sequential silanolysis/alcoholysis process or unprecedented dehydrocoupling between germanol hydrosilane.

Язык: Английский

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