Enantioselective electrochemical cobalt-catalyzed aryl C–H activation reactions

Science, Journal Year: 2023, Volume and Issue: 379(6636), P. 1036 - 1042

Published: March 10, 2023

Enantioselective redox transformations typically rely on costly transition metals as catalysts and often stoichiometric amounts of chemical agents well. Electrocatalysis represents a more sustainable alternative, in particular through the use hydrogen evolution reaction (HER) place oxidant. In this work, we describe strategies for HER-coupled enantioselective aryl carbon-hydrogen bond (C-H) activation reactions using cobalt precious metal catalyst asymmetric oxidation. Thus, highly nitrogen-hydrogen (C-H N-H) annulations carboxylic amides were achieved, which gave access to point axially chiral compounds. Furthermore, cobalt-mediated electrocatalysis enabled preparation various phosphorus (P)-stereogenic compounds by selective desymmetrization dehydrogenative C-H reactions.

Language: Английский

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Enantio‐ and Regioselective Electrooxidative Cobalt‐Catalyzed C−H/N−H Annulation with Alkenes

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(11)

Published: Jan. 20, 2023

In recent years, the merging of electrosynthesis with 3d metal catalyzed C-H activation has emerged as a sustainable and powerful technique in organic synthesis. Despite impressive advantages, development an enantioselective version remains elusive poses daunting challenge. Herein, we report first electrooxidative cobalt-catalyzed enantio- regioselective C-H/N-H annulation olefins using undivided cell at room temperature (up to 99 % ee). t Bu-Salox, rationally designed Salox ligand bearing bulky tert-butyl group ortho-position phenol, was found be crucial for this asymmetric reaction. A strong cooperative effect between Bu-Salox 3,4,5-trichloropyridine enabled highly more challenging α-olefins without secondary bond interactions 96 ee 97 : 3 rr). Cyclovoltametric studies, preparation, characterization, transformation cobaltacycle intermediates shed light on mechanism

Language: Английский

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Base‐Promoted Electrochemical Co^II‐catalyzed Enantioselective C−H Oxygenation

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(21)

Published: March 20, 2023

Metalla-electrocatalyzed C-H oxygenation represents one of the most straightforward and sustainable approaches to access valuable oxygenated molecules. Despite significant advances, development enantioselective electrochemical reaction is very challenging remains elusive. Herein, we described first CoII -catalyzed alkoxylation. A broad range enantioenriched alkoxylated phosphinamides were obtained in good yields with excellent enantioselectivities (up 98 % yield >99 ee). An unusual cobalt(III) alcohol complex was prepared fully characterized, which proven be a key intermediate this alkoxylation reaction. Mechanistic studies revealed that oxidation CoIII CoIV facilitated by base whole process proceeded through cobalt(III/IV/II) catalytic cycle.

Language: Английский

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Cobalt-catalyzed atroposelective C−H activation/annulation to access N−N axially chiral frameworks

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: Aug. 29, 2023

The N-N atropisomer, as an important and intriguing chiral system, was widely present in natural products, pharmaceutical lead compounds, advanced material skeletons. anisotropic structural characteristics caused by its special axial rotation have always been one of the challenges that chemists strive to overcome. Herein, we report efficient method for enantioselective synthesis axially frameworks via a cobalt-catalyzed atroposelective C-H activation/annulation process. reaction proceeds under mild conditions using Co(OAc)2·4H2O catalyst with salicyl-oxazoline (Salox) ligand O2 oxidant, affording variety products high yields enantioselectivities. This protocol provides approach facile construction atropisomers further expands range derivatives. Additionally, electrocatalysis, desired were also successfully achieved good excellent efficiencies

Language: Английский

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Cobalt-Catalyzed Enantioselective C–H Annulation with Alkenes

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(7), P. 4250 - 4260

Published: March 13, 2023

Herein, we disclose an efficient cobalt-catalyzed enantioselective C–H activation and annulation of benzamides with alkenes. This transformation is facilitated via the commercially available cobalt(II) catalyst in presence easily prepared chiral salicyl-oxazoline (Salox) ligand, which provides facile access to (R) or (S) enantiomers dihydroisoquinolone derivatives. It noticeable that reaction proceeded efficiently within extremely short time from 10 30 min under mild conditions. A broad range alkenes bear various functional substituents have been shown good compatibility deliver targeted products high yields enantioselectivities (51 examples, up 98% yield 99% ee). The gram scale experiment removal directing group further demonstrate practicability this protocol potential industrial applications. Density theory calculations elucidate mechanism, spin-state change olefin insertion step accelerates subsequent C–N reductive elimination, identified as stereo-determining step. AIM analysis indicates π interactions are vital for controlling switching stereoselectivity.

Language: Английский

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Electrooxidative Rhodium(III)/Chiral Carboxylic Acid‐Catalyzed Enantioselective C−H Annulation of Sulfoximines with Alkynes

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(15)

Published: Jan. 30, 2024

Abstract The combination of achiral Cp*Rh(III) with chiral carboxylic acids (CCAs) represents an efficient catalytic system in transition metal‐catalyzed enantioselective C−H activation. However, this hybrid catalysis is limited to redox‐neutral activation reactions and the adopt oxidative remains elusive pose a significant challenge. Herein, we describe development electrochemical Cp*Rh(III)‐catalyzed annulation sulfoximines alkynes enabled by acid (CCA) operationally friendly undivided cell at room temperature. A broad range enantioenriched 1,2‐benzothiazines are obtained high yields excellent enantioselectivities (up 99 % yield 98 : 2 er). practicality method demonstrated scale‐up reaction batch reactor external circulation. crucial intermediate isolated, characterized, transformed, providing rational support for Rh(III)/Rh(I) electrocatalytic cycle.

Language: Английский

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Cobalt‐Catalyzed Enantioselective C−H Carbonylation towards Chiral Isoindolinones

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(10)

Published: Jan. 11, 2024

Transition metal-catalyzed enantioselective C-H carbonylation with carbon monoxide, an essential and easily available C1 feedstock, remains challenging. Here, we disclosed unprecedented catalyzed by inexpensive readily cobalt(II) salt. The reactions proceed efficiently through desymmetrization, kinetic resolution, parallel affording a broad range of chiral isoindolinones in good yields excellent enantioselectivities (up to 92 % yield 99 ee). synthetic potential this method was demonstrated asymmetric synthesis biological active compounds, such as (S)-PD172938 (S)-Pazinaclone. resulting also serve ligands cobalt-catalyzed annulation alkynes construct phosphorus stereocenter.

Language: Английский

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Cobalt(III)-Catalyzed Enantioselective C–H Functionalization: Ligand Innovation and Reaction Development

Accounts of Chemical Research, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 26, 2025

ConspectusIn contrast to precious transition metals, such as palladium and rhodium, the development of novel chiral ligands for enantioselective C-H functionalizations catalyzed by earth-abundant, cost-effective, environmentally friendly 3d metals poses substantial challenges, primarily due variable oxidation states, intricate coordination patterns, limited mechanistic insights. In this Account, we summarize our research endeavors in three types Co(III) catalysis: pseudotetrahedral achiral Cp*Co(III)/chiral carbonyl acid (CCA) catalysis, situ-generated octahedral cobalt(III) via cobalt/salicyloxazoline (Salox) Co(II)/chiral phosphoric (CPA) cooperative achieved through strategic ligand design. Our initial objective was achieve functionalization Cp*Co(III) catalysts with external ligands, aiming circumvent laborious preparation CpxCo(III) complexes. To end, developed several CCA incorporating non-covalent interactions (NCIs) a crucial design element. Next, address limitations associated lengthy synthesis Cp-ligated complexes difficulties modification, explored concept situ generation catalysis using commercially available cobalt(II) salts tailor-made ligands. This exploration led two innovative catalytic systems, namely, Co(II)/Salox Co(II)/CCA sequential catalysis. The emerged versatile strategy, demonstrating excellent enantioselectivities across range asymmetric reactions construct various molecules central, axial, planar, inherent chirality. facile single step, along ease further enhances versatility applicability approach. Moreover, successfully applied cobalt/Salox electro- photochemical-catalyzed functionalization, electrons or oxygen traceless oxidant, thereby eliminating need stoichiometric chemical oxidants. Through studies reaction developments, elucidated detailed structure-enantioselectivity relationships which are expected inform future endeavors. Finally, Co(II)/CPA enabled spiro-γ-lactams olefination/asymmetric [4 + 1] spirocyclization. Mechanistically, establishment stereochemistry occurs during cyclization where CPA serves both neutral Brønsted acid, stereoinduction independent cleavage step. We anticipate that insights advancements Account will inspire innovations drive progress metal-catalyzed reactions.

Language: Английский

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Synthesis of Sulfur-Stereogenic Sulfoximines via Co(III)/Chiral Carboxylic Acid-Catalyzed Enantioselective C–H Amidation

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(15), P. 9806 - 9811

Published: July 27, 2022

Sulfoximines bearing stereogenic sulfur atoms are ubiquitous motifs in pharmaceuticals, agricultural chemicals, and bioactive compounds. Herein, we report the synthesis of sulfur-stereogenic sulfoximines via Co(III)/chiral carboxylic acid-catalyzed enantioselective C–H amidation. A broad range cyclic acyclic were isolated good yields enantioselectivities (up to an 86% yield 1.5:98.5 er). The amidation products can be reduced potential N,S-chiral sulfoxide ligands, which could further transformed into recyclable chiral auxiliaries Pd-catalyzed diastereoselective C(sp3)–H activation aliphatic acids.

Language: Английский

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Ruthenium(II)/Imidazolidine Carboxylic Acid‐Catalyzed C−H Alkylation for Central and Axial Double Enantio‐Induction

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(47)

Published: Sept. 15, 2022

Enantioselective C-H activation has surfaced as a transformative toolbox for the efficient assembly of chiral molecules. However, despite major advances in rhodium and palladium catalysis, ruthenium(II)-catalyzed enantioselective thus far largely proven elusive. In contrast, we herein report on highly regio-, diastereo- alkylation. The key to success was represented by identification novel C2-symmetric imidazolidine carboxylic acids (CICAs), which are easily accessible one-pot fashion, effective ligands. This ruthenium/CICA system enabled installation central axial chirality, featured excellent branched linear ratios with generally >20 : 1 dr up 98 2 er. Mechanistic studies experiment computation were carried out understand catalyst mode action.

Language: Английский

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