Photoinduced Cobalt Catalysis for the Reductive Coupling of Pyridines and Dienes Enabled by Paired Single‐Electron Transfer** DOI Creative Commons

Jingyang Qin,

Manuel Barday,

Samikshan Jana

et al.

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(45)

Published: Sept. 7, 2023

Abstract Selective hydroarylation of dienes has potential to provide swift access useful building blocks. However, most existing methods rely on stabilised by an aromatic group and transmetallation or nucleophilic attack steps require electron‐rich aryl coupling partners. As such, there are few examples which tolerate wide‐spread heteroarenes such as pyridine. Whilst allylic C−H functionalisation could be considered alternative approach, the positional selectivity unsymmetrical substrates is hard control. Here, we report a general approach for selective hydropyridylation under mild conditions using metal catalysed hydrogen‐atom transfer. Photoinduced, reductive enable simultaneous formation cobalt‐hydride catalyst persistent radical easily‐synthesised pyridyl phosphonium salts. This facilitates in traceless manner at C4‐position wide‐range pyridine substrates. The mildness method underscored its functional‐group tolerance demonstrated applications late‐stage functionalisation. Based combination experimental computational studies, propose mechanistic pathway proceeds through non‐reversible transfer (HAT) from cobalt hydride species uniquely presence other olefins due much higher relative barrier associated with olefin HAT.

Language: Английский

Catalytic Asymmetric Hydroalkoxylation of C–C Multiple Bonds DOI Creative Commons
Jennifer L. Kennemur, Rajat Maji, Manuel J. Scharf

et al.

Chemical Reviews, Journal Year: 2021, Volume and Issue: 121(24), P. 14649 - 14681

Published: Dec. 3, 2021

Asymmetric hydroalkoxylation of alkenes constitutes a redox-neutral and 100% atom-economical strategy toward enantioenriched oxygenated building blocks from readily available starting materials. Despite their great potential, catalytic enantioselective additions alcohols across C–C multiple bond are particularly underdeveloped, especially compared to other hydrofunctionalization methods such as hydroamination. However, driven by some recent innovations, e.g., asymmetric MHAT methods, photocatalytic the development extremely strong chiral Brønsted acids, there has been gratifying surge reports in this burgeoning field. The goal review is survey growing landscape highlighting exciting new advances, deconstructing mechanistic underpinnings, drawing insight related hydroacyloxylation hydration. A deep appreciation underlying principles informs an understanding various selectivity parameters activation modes realm alkene while simultaneously evoking outstanding challenges field moving forward. Overall, we aim lay foundation for cross-fertilization among fields spur further innovation hydroalkoxylations bonds.

Language: Английский

Citations

97
Electrocatalytic Oxidative Hydrofunctionalization Reactions of Alkenes via Co(II/III/IV) Cycle DOI
Fan Yang, Yi-Chen Nie, Han-Yuan Liu

et al.

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(4), P. 2132 - 2137

Published: Jan. 27, 2022

Here we disclose a general Co(II/III/IV) electrocatalytic platform for alkene functionalization. Driven by electricity, set of the oxidative hydrofunctionalization reactions via hydrogen atom transfer were demonstrated without need stochiometric chemical oxidants. The scope encompasses hydroalkoxylation, hydroacyloxylation, hydroarylation, semipinacol rearrangement, and deallylation. Mechanistic studies stereochemical evidence support an ECEC process involving electrochemically generated organocobalt(IV) intermediate. This work presents example reactivity space expansion in electrocatalysis VB12-system going beyond common oxidation states Co(I/II/III).

Language: Английский

Citations

60
Cobalt–Carbon Bonding in a Salen-Supported Cobalt(IV) Alkyl Complex Postulated in Oxidative MHAT Catalysis DOI

Conner V. Wilson,

Dongyoung Kim, Ajay Sharma

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(23), P. 10361 - 10367

Published: June 3, 2022

The catalytic hydrofunctionalization of alkenes through radical-polar crossover metal hydrogen atom transfer (MHAT) offers a mild pathway for the introduction functional groups in sterically congested environments. For M = Co, this reaction is often proposed to proceed secondary alkylcobalt(IV) intermediates, which have not been characterized unambiguously. Here, we characterize metastable (salen)Co(isopropyl) cation, capable forming C-O bonds with alcohols as reaction. Electron nuclear double resonance (ENDOR) spectroscopy formally cobalt(IV) species establishes presence cobalt-carbon bond, and accompanying DFT calculations indicate that unpaired electron localized on cobalt center. Both experimental computational studies show cobalt(IV)-carbon bond stronger than analogous its cobalt(III) analogue, opposite usual oxidation state trend energies. This phenomenon attributable an inverted ligand field gives Coδ--Cδ+ character explains electrophilic reactivity at alkyl group. Co-C polarity also stabilizes complex so it accessible unusually low potentials. Even another complex, [(salen)CoIII]+, oxidizing (salen)CoIII(iPr) state. These results give insight into electronic structure, energetics, key reactive intermediate oxidative MHAT catalysis.

Language: Английский

Citations

54
Divergent Total Syntheses of (−)-Crinipellins Facilitated by a HAT-Initiated Dowd–Beckwith Rearrangement DOI
Yifan Zhao, Jialei Hu, Ruyi Chen

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(6), P. 2495 - 2500

Published: Feb. 3, 2022

A hydrogen atom transfer (HAT)-initiated Dowd-Beckwith rearrangement reaction was developed, which enables the efficient assembly of diversely functionalized polyquinane frameworks. By incorporation an iridium-catalyzed regio- and enantioselective hydrogenation a diastereocontrolled ODI-[5+2] cycloaddition/pinacol cascade reaction, asymmetric total syntheses eight tetraquinane natural products, including (-)-crinipellins A-F (-)-dihydrocrinipellins B, have been achieved in concise divergent manner.

Language: Английский

Citations

53
Cobalt‐Catalyzed Asymmetric Alkylation of (Hetero)Arenes with Styrenes DOI
Tao Qin, Guowei Lv,

Huanran Miao

et al.

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(26)

Published: April 1, 2022

An efficient and general intermolecular Cobalt(II)-catalyzed asymmetric alkylation of styrenes with (hetero)arenes including indoles, thiophene electron rich arenes has been developed, providing straightforward access to enantioenriched alkyl(hetero)arenes high enantioselectivity. Mechanistic studies suggest that the reaction underwent a CoH-mediated hydrogen atom transfer (HAT) alkenes, followed by pivotal catalyst-controlled SN 2-like pathway between in situ generated organocobalt(IV) species aromatic nucleophiles. This is first CoH-catalyzed hydrofunctionalization using carbon nucleophiles, new strategy for Friedel-Crafts type alkylation.

Language: Английский

Citations

50
Asymmetric C–H Dehydrogenative Allylic Alkylation by Ternary Photoredox-Cobalt-Chiral Primary Amine Catalysis under Visible Light DOI

Zongbin Jia,

Long Zhang, Sanzhong Luo

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(24), P. 10705 - 10710

Published: June 8, 2022

We report herein an asymmetric C–H dehydrogenative allylic alkylation by a synergistic catalytic system involving chiral primary amine, photoredox catalyst, and cobaloxime cocatalyst. The ternary enables the coupling of β-ketocarbonyls olefins with good yields high enantioselectivities. Mechanism studies disclosed cooperative radical addition process α-imino Co(II)-metalloradical wherein aminocatalyst catalyst work in concert to control stereoinduction.

Language: Английский

Citations

45
Electrocatalytic Radical-Polar Crossover Hydroetherification of Alkenes with Phenols DOI
Steve Park,

Jieun Jang,

Kwangmin Shin

et al.

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(17), P. 10572 - 10580

Published: Aug. 12, 2022

We disclose a general electrocatalytic hydroetherification for modular synthesis of alkyl aryl ethers by utilizing wide range alkenes and phenols. The integration the two involves an electrochemically instigated cobalt-hydride-catalyzed radical-polar crossover that enable generation key cationic intermediates, which could readily be entrapped challenging nucleophilic highlight importance precise control reaction potential electrochemistry in conjunction with decisive role 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as co-solvent to obtain optimal exclusive chemoselectivity. This system is pertinent late-stage functionalization pharmacophores contain have constantly been challenged since traditionally unconventional methods.

Language: Английский

Citations

45
Cobalt‐Catalyzed Enantioselective Hydroamination of Arylalkenes with Secondary Amines DOI

Huanran Miao,

Meihui Guan,

Tao Xiong

et al.

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 62(2)

Published: Nov. 7, 2022

Abstract Catalytic asymmetric hydroamination of alkenes with Lewis basic amines is great interest but remains a challenge in synthetic chemistry. Here, we developed Co‐catalyzed arylalkenes directly using commercially accessible secondary amines. This process enables the efficient access to valuable α ‐chiral tertiary good excellent yields and enantioselectivities. Mechanistic studies suggest that reaction includes CoH‐mediated hydrogen atom transfer (MHAT) arylalkenes, followed by pivotal catalyst controlled S N 2‐like pathway between situ generated electrophilic cationic alkylcobalt(IV) species free radical‐polar crossover strategy not only provides straightforward alternative approach for synthesis enantioenriched ‐tertiary amines, also underpins substantial opportunities developing radical functionalization various nucleophiles oxidative MHAT catalysis.

Language: Английский

Citations

44
Light-Driven Cobalt Hydride Catalyzed Hydroarylation of Styrenes DOI
Enrico Bergamaschi,

Victor J. Mayerhofer,

Christopher J. Teskey

et al.

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(24), P. 14806 - 14811

Published: Nov. 22, 2022

We report a conceptually distinct strategy for the synthesis of 1,1-diarylalkanes and triarylalkanes. Key to this approach is use light simultaneously trigger (i) formation CoIII–H species which undergoes H atom transfer (MHAT) styrenes, giving carbon-centered radical, (ii) generation persistent (hetero)arene radical. Selective coupling these two yields Markovnikov hydroarylation products under mild conditions without precious metals. In contrast many previous approaches, electron-deficient partners are favored it possible construct highly congested quaternary centers, including those with three different aryl groups.

Language: Английский

Citations

43
Branched-Selective Hydroacylation of Alkenes via Photoredox Cobalt and N-Heterocyclic Carbene Cooperative Triple Catalysis DOI
Xiangzhang Tao, Qing Wang, Lingyu Kong

et al.

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(24), P. 15241 - 15248

Published: Nov. 29, 2022

A Markovnikov-selective hydroacylation of alkenes has been achieved via the synergistic merger cobalt, photoredox and N-heterocyclic carbene catalysis. The closely incorporated catalytic cycles allow for Co(III) generation by photochemical oxidation instead chemical oxidants or anodizing process. This mild, operationally simple protocol converts a wide variety commercially available aroyl fluorides into corresponding ketones in high yield with branched selectivity.

Language: Английский

Citations

42