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

Advanced Synthesis & Catalysis, Journal Year: 2017, Volume and Issue: 359(8), P. 1245 - 1262

Published: March 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

Language: Английский

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Catalytic Transformations of Functionalized Cyclic Organic Carbonates

Angewandte Chemie International Edition, Journal Year: 2018, Volume and Issue: 57(42), P. 13735 - 13747

Published: June 6, 2018

Functionalized cyclic organic carbonates and related heterocycles have emerged as highly versatile heterocyclic substrates for ring-opening decarboxylative catalytic transformations allowing the development of new stereo- enantioselective C-N, C-O, C-C, C-S C-B bond formation reactions. Transition-metal-mediated conversions only recently been rejuvenated powerful approaches towards preparation more complex molecules. This minireview will highlight potential structurally with a focus on their synthetic value mechanistic manifolds that are involved upon conversion.

Language: Английский

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C–H functionalization by high-valent Cp*Co(iii) catalysis

Chemical Communications, Journal Year: 2017, Volume and Issue: 53(22), P. 3165 - 3180

Published: Jan. 1, 2017

Significant progress has been accomplished in directed C–H functionalization through the use of earth-abundant and inexpensive first-row transition metals.

Language: Английский

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Direct Functionalization of C−H Bonds by Iron, Nickel, and Cobalt Catalysis

Chemistry - A European Journal, Journal Year: 2017, Volume and Issue: 23(39), P. 9206 - 9232

Published: June 7, 2017

Abstract Non‐precious‐metal‐catalyzed reactions are of increasing importance in chemistry due to the outstanding ecological and economic properties these metals. In subfield metal‐catalyzed direct C−H functionalization reactions, recent years have shown an number publications dedicated this topic. Nickel, cobalt, last but not least iron, started enter a field which was long dominated by precious metals such as palladium, rhodium, ruthenium, iridium. The present review article summarizes development iron‐, nickel‐, cobalt‐catalyzed until end 2016, discusses scope limitations transformations.

Language: Английский

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Overcoming the Limitations of C−H Activation with Strongly Coordinating N‐Heterocycles by Cobalt Catalysis

Angewandte Chemie International Edition, Journal Year: 2016, Volume and Issue: 55(35), P. 10386 - 10390

Published: July 21, 2016

Abstract Strongly coordinating nitrogen heterocycles, including pyrimidines, oxazolines, pyrazoles, and pyridines, were fully tolerated in cobalt‐catalyzed C−H amidations by imidate assistance. Structurally complex quinazolines are thus accessible a step‐economic manner. Our findings also establish the relative powers of directing groups cobalt(III)‐catalyzed functionalization for first time.

Language: Английский

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Unnatural Amino Acid Synthesis Enabled by the Regioselective Cobalt(III)‐Catalyzed Intermolecular Carboamination of Alkenes

Angewandte Chemie International Edition, Journal Year: 2016, Volume and Issue: 55(48), P. 15166 - 15170

Published: Oct. 27, 2016

Abstract Herein, we report an unprecedented regioselective and entirely atom‐economic cobalt(III)‐catalyzed method for the non‐annulative, intermolecular carboamination of alkenes. The methodology enables direct synthesis unnatural amino acid derivatives proceeds under redox‐neutral conditions with a completely C−C bond C−N formation. Furthermore, this reaction exemplifies inherently different mechanistic behavior Cp*Co III catalyst its Cp*Rh counterpart, especially towards β‐H‐elimination.

Language: Английский

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Amidines for Versatile Cobalt(III)-Catalyzed Synthesis of Isoquinolines through C–H Functionalization with Diazo Compounds

Organic Letters, Journal Year: 2016, Volume and Issue: 18(11), P. 2742 - 2745

Published: May 24, 2016

A cobalt(III)-catalyzed C–H/N–H bond functionalization for the synthesis of 1-aminoisoquinolines from aryl amidines and diazo compounds has been developed. The reaction proceeds under mild conditions, obviates need oxidants, produces only N2 H2O as byproducts, features a broad substrate scope.

Language: Английский

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Cobalt‐Catalyzed Annulation Reactions via C−H Bond Activation

ChemCatChem, Journal Year: 2017, Volume and Issue: 10(4), P. 683 - 705

Published: Nov. 1, 2017

Abstract Considerable research attention has been directed towards the use of first‐row transition metals in organic synthesis. The more abundant, and less expensive cobalt is considered to be an effective alternative for second third‐row noble metals, especially C−H bond functionalization reactions. In this Minireview, we will summarize features, recent achievements Co‐catalyzed directing group assisted activation/cyclization reactions their mechanistic insights.

Language: Английский

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Why is the Ir(III)-Mediated Amido Transfer Much Faster Than the Rh(III)-Mediated Reaction? A Combined Experimental and Computational Study

Journal of the American Chemical Society, Journal Year: 2016, Volume and Issue: 138(42), P. 14020 - 14029

Published: Oct. 3, 2016

The mechanism of the Ir(III)- and Rh(III)-mediated C–N coupling reaction, which is key step for catalytic C–H amidation, was investigated in an integrated experimental computational study. Novel amidating agents containing a 1,4,2-dioxazole moiety allowed designing stoichiometric version reaction giving access to intermediates that reveal details about each reaction. Both DFT kinetic studies strongly point where M(III)-complex engages agent via oxidative form M(V)–imido intermediate, then undergoes migratory insertion afford final coupled product. For first time, versions Ir- Rh-mediated amidation were compared systematically other. Iridium reacts much faster than rhodium (∼1100 times at 6.7 °C) with being so fast activation initial Ir(III)-complex becomes rate-limiting. In case Rh, Rh–imido formation These qualitative differences stem from unique bonding feature dioxazole relativistic contraction Ir(V), affords more favorable energetics full molecular orbital analysis presented rationalize explain electronic features govern this behavior.

Language: Английский

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Thioamide‐Directed Cobalt(III)‐Catalyzed Selective Amidation of C(sp³)−H Bonds

Angewandte Chemie International Edition, Journal Year: 2017, Volume and Issue: 56(52), P. 16550 - 16554

Published: Oct. 28, 2017

A mild, oxidant-free, and selective Cp*CoIII -catalyzed amidation of thioamides with robust dioxazolone amidating agents via C(sp3 )-H bond activation to generate the desired amidated products is reported. The method efficient allows for C-H a wide range functionalized aryl-, heteroaryl-, alkyl-substituted dioxazolones under conditions. observed regioselectivity towards primary supported by computational studies cyclometalation proposed proceed means an external carboxylate-assisted concerted metalation/deprotonation mechanism. reported rare example use directing group other than commonly used pyridine quinolone classes functionalization first exploit thioamides.

Language: Английский

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