(Pentamethylcyclopentadienyl)cobalt(III)‐Catalyzed C–H Bond Functionalization: From Discovery to Unique Reactivity and Selectivity

Advanced Synthesis & Catalysis, Год журнала: 2017, Номер 359(8), С. 1245 - 1262

Опубликована: Март 16, 2017

Abstract High‐valent (pentamethylcyclopentadienyl)cobalt(III) [Cp*Co(III)] catalysts were found as inexpensive alternatives to (pentamethylcyclopentadienyl)rhodium(III) [Cp*Rh(III)] in the field of C—H bond functionalization, and applied a variety transformations. In this review, after discovery early examples Cp*Co(III)‐catalyzed functionalization are summarized, unique reactivity selectivity Cp*Co(III) differences between cobalt rhodium catalysis intensively discussed. Such assumed be caused by lower electronegativity, hard nature, smaller ionic radius cobalt. magnified image

Язык: Английский

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Recent advances in the synthesis of axially chiral biarylsviatransition metal-catalysed asymmetric C–H functionalization

Chemical Communications, Год журнала: 2019, Номер 55(59), С. 8514 - 8523

Опубликована: Янв. 1, 2019

Recent advances in the synthesis of axially chiral biarylsviatransition metal-catalysed asymmetric C–H functionalization are reported.

Язык: Английский

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Enantioselective C−H Activation with Earth‐Abundant 3d Transition Metals

Angewandte Chemie International Edition, Год журнала: 2019, Номер 58(37), С. 12803 - 12818

Опубликована: Май 11, 2019

Molecular syntheses largely rely on time- and labour-intensive prefunctionalization strategies. In contrast, C-H activation represents an increasingly powerful approach that avoids lengthy of prefunctionalized substrates, with great potential for drug discovery, the pharmaceutical industry, material sciences, crop protection, among others. The enantioselective functionalization omnipresent bonds has emerged as a transformative tool step- atom-economical generation chiral molecular complexity. However, this rapidly growing research area remains dominated by noble transition metals, prominently featuring toxic palladium, iridium rhodium catalysts. Indeed, despite significant achievements, use inexpensive sustainable 3d metals in asymmetric activations is still clearly its infancy. Herein, we discuss remarkable recent progress transformations via organometallic base up to April 2019.

Язык: Английский

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Synthesis and Application of Chiral Spiro Cp Ligands in Rhodium-Catalyzed Asymmetric Oxidative Coupling of Biaryl Compounds with Alkenes

Journal of the American Chemical Society, Год журнала: 2016, Номер 138(16), С. 5242 - 5245

Опубликована: Апрель 12, 2016

The vastly increasing application of chiral Cp ligands in asymmetric catalysis results growing demand for novel ligands. Herein, we report a new class based on 1,1′-spirobiindane, privileged scaffold and catalysts. corresponding Rh complexes are shown to be excellent catalysts oxidative coupling reactions, providing axially biaryls 19–97% yields with up 98:2 er.

Язык: Английский

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Rhodium‐Catalyzed C(sp²)‐ or C(sp³)−H Bond Functionalization Assisted by Removable Directing Groups

Angewandte Chemie International Edition, Год журнала: 2018, Номер 58(25), С. 8304 - 8329

Опубликована: Окт. 12, 2018

Abstract In recent years, transition‐metal‐catalyzed C−H activation has become a key strategy in the field of organic synthesis. Rhodium complexes are widely used as catalysts variety functionalization reactions because their high reactivity and selectivity. The availability number rhodium various oxidation states enables diverse reaction patterns to be obtained. Regioselectivity, an important issue chemistry, can accomplished by using directing group assist reaction. However, obtain target functionalized compounds, it is also necessary use that easily removed. A wide range directed catalyzed have been reported date. this Review, we discuss Rh‐catalyzed aided removable such phenol, amine, aldehyde, ketones, ester, acid, sulfonic N‐heteroaromatic derivatives.

Язык: Английский

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Recent advances in positional-selective alkenylations: removable guidance for twofold C–H activation

Organic Chemistry Frontiers, Год журнала: 2017, Номер 4(7), С. 1435 - 1467

Опубликована: Янв. 1, 2017

Recent advances in transition-metal catalyzed positional-selective alkenylations via twofold C–H activation directed by removable or traceless directing groups are reviewed.

Язык: Английский

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N-Acyl Amino Acid Ligands for Ruthenium(II)-Catalyzed meta-C–H tert-Alkylation with Removable Auxiliaries

Journal of the American Chemical Society, Год журнала: 2015, Номер 137(43), С. 13894 - 13901

Опубликована: Сен. 29, 2015

Acylated amino acid ligands enabled ruthenium(II)-catalyzed C-H functionalizations with excellent levels of meta-selectivity. The outstanding catalytic activity the ruthenium(II) complexes derived from monoprotected acids (MPAA) set stage for first ruthenium-catalyzed meta-functionalizations removable directing groups. Thereby, meta-alkylated anilines could be accessed, which are difficult to prepare by other means direct aniline functionalizations. robust nature versatile ruthenium(II)-MPAA was reflected challenging remote transformations tertiary alkyl halides on derivatives as well pyridyl-, pyrimidyl-, and pyrazolyl-substituted arenes. Detailed mechanistic studies provided strong support an initial reversible ruthenation, followed a SET-type C-Hal activation through homolytic bond cleavage. Kinetic analyses confirmed this hypothesis unusual second-order dependence reaction rate ruthenium catalyst concentration. Overall, report highlights exceptional acylated acids, should prove instrumental chemistry beyond functionalization.

Язык: Английский

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Electronic and Steric Tuning of a Prototypical Piano Stool Complex: Rh(III) Catalysis for C–H Functionalization

Accounts of Chemical Research, Год журнала: 2017, Номер 51(1), С. 170 - 180

Опубликована: Дек. 22, 2017

ConspectusThe history of transition metal catalysis is heavily steeped in ligand design, clearly demonstrating the importance this approach. The intimate relationship between and can profoundly affect outcome a reaction, often impacting selectivity, physical properties, lifetime catalyst. Importantly, metal–ligand provide near limitless opportunities for reaction discovery. Over past several years, transition-metal-catalyzed C–H bond functionalization reactions have been established as critical foundation organic chemistry that provides new forming strategies. Among d-block elements, palladium arguably one most popular metals to accomplish such transformations. One possible explanation achievement could be broad set phosphine amine based ligands available chemist's toolbox compatible with palladium. In parallel, other investigated functionalization. them, pentamethylcyclopentadienyl (Cp*) Rh(III) complexes emerged powerful mode transformations providing spectrum reactivity. This approach possesses advantage very low catalyst loading, are typically performed under mild conditions allowing functional group tolerance. Cp*Rh(III) considered privileged plethora involving cleavage event developed. search alternative cyclopentadienyl has eclipsed by tremendous effort devoted exploring considerable scope catalyzed complexes, despite potential strategy enabling Thus, modification efforts an exception research directed toward rhodium catalysts sparse. Recently, chiral appeared enantioselective Rh(III)-catalyzed performed. Alongside ligands, equally important collection achiral cyclopentadienyl-derived also emerged. design already translated significant success solving inherent problems reactivity selectivity encountered throughout development Account describes evolution skeletons Rh(III)-catalysis since introduction present. Specific emphasis placed on synthetic applications achieved mono-, di-, or pentasubstituted exhibiting stunning effect selectivity. Furthermore, underlying question when dealing strategies explain reason outperforms another. Conjecture speculation abound, but extensive characterization their steric electronic properties carried out information about all contribute our understanding give crucial pieces solve puzzle.

Язык: Английский

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Access to P‐ and Axially Chiral Biaryl Phosphine Oxides by Enantioselective Cp^xIr^III‐Catalyzed C−H Arylations

Angewandte Chemie International Edition, Год журнала: 2018, Номер 57(39), С. 12901 - 12905

Опубликована: Июль 25, 2018

An enantioselective C-H arylation of phosphine oxides with o-quinone diazides catalyzed by an iridium(III) complex bearing atropchiral cyclopentadienyl (Cpx ) ligand and phthaloyl tert-leucine as co-catalyst is reported. The method allows access to a) P-chiral biaryl oxides, b) atropo-enantioselective construction sterically demanding backbones, also c) selective assembly axial compounds in excellent yields diastereo- enantioselectivities. Enantiospecific reductions provide monodentate chiral phosphorus(III) having structures backbones proven importance ligands asymmetric catalysis.

Язык: Английский

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General Enantioselective C−H Activation with Efficiently Tunable Cyclopentadienyl Ligands

Angewandte Chemie International Edition, Год журнала: 2017, Номер 56(9), С. 2429 - 2434

Опубликована: Янв. 26, 2017

Abstract Cyclopentadienyl (Cp) ligands enable efficient steering of various transition‐metal‐catalyzed transformations, in particular enantioselective C−H activation. Currently only few chiral Cp are available. Therefore, a conceptually general approach to ligand discovery would be invaluable as it the applicable and efficiently rapidly vary tune their structures. Herein, we describe three‐step gram‐scale synthesis structurally diverse widely collection (JasCp ligands) with highly variable adjustable Their modular nature amenability rapid structure variation enabled for three Rh III ‐catalyzed activation reactions, including one unprecedented transformation. This novel should further transformations.

Язык: Английский

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