Cobalt‐Catalyzed Photo‐Semipinacol Rearrangement of Unactivated Allylic Alcohols DOI Creative Commons
Henry Lindner, Erick M. Carreira

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(35)

Published: June 7, 2024

We report a photochemical method for the semipinacol rearrangement of unactivated allylic alcohols. Aliphatic as well aromatic groups participate migrating groups, yielding variety α,α-disubstituted ketones. The reaction proceeds under mild conditions and is compatible with ethers, esters, halides, nitriles, carbamates, substituted arenes. operationally simple fully catalytic prescribe 1 mol % benzothiazinoquinoxaline organophotocatalyst, 0.5 Co-salen, 10 lutidinium triflate and, importantly, display reactivity complementary to procedures employing Brønsted acid. showcase utility protocol in late-stage drug diversifications.

Language: Английский

Photo‐ and Electrochemical Cobalt Catalysed Hydrogen Atom Transfer for the Hydrofunctionalisation of Alkenes DOI Creative Commons

Samikshan Jana,

Victor J. Mayerhofer,

Christopher J. Teskey

et al.

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(41)

Published: May 15, 2023

Catalytic hydrogen atom transfer from metal-hydrides to alkenes allows feedstock olefins be used as alkyl radical precursors. The chemoselectivity of this process makes it an attractive synthetic tool and such has been regularly in synthesis complex molecules. However, onwards reactivity is limited by compatibility with the conditions which form key metal-hydride species. Now, through merger photocatalysis or electrochemistry, milder methods are emerging can unlock entirely new offer perspectives on expanding these unprecedented directions. This review outlines most recent developments electro- photochemical cobalt catalysed offers suggestions future outlook.

Language: Английский

Citations

58
Electrocatalytic Access to Azetidines via Intramolecular Allylic Hydroamination: Scrutinizing Key Oxidation Steps through Electrochemical Kinetic Analysis DOI
Steve Park, Geunsu Bae,

Ahhyeon Choi

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(28), P. 15360 - 15369

Published: July 10, 2023

Azetidines are prominent structural scaffolds in bioactive molecules, medicinal chemistry, and ligand design for transition metals. However, state-of-the-art methods cannot be applied to intramolecular hydroamination of allylic amine derivatives despite their underlying potential as one the most prevalent synthetic precursors azetidines. Herein, we report an electrocatalytic method sulfonamides access azetidines first time. The merger cobalt catalysis electricity enables regioselective generation key carbocationic intermediates, which could directly undergo C-N bond formation. mechanistic investigations including electrochemical kinetic analysis suggest that either catalyst regeneration by nucleophilic cyclization or second oxidation intermediate is involved rate-determining step (RDS) our protocol highlight ability electrochemistry providing ideal means mediate oxidation.

Language: Английский

Citations

58
Intermolecular Organophotocatalytic Cyclopropanation of Unactivated Olefins DOI Creative Commons
David M. Fischer, Henry Lindner, Willi M. Amberg

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(2), P. 774 - 780

Published: Jan. 6, 2023

Intermolecular cyclopropanation of mono-, di-, and trisubstituted olefins with α-bromo-β-ketoesters α-bromomalonates under organophotocatalysis is reported. The reaction displays broad functional group tolerance, including substrates bearing acids, alcohols, halides, ethers, ketones, nitriles, esters, amides, carbamates, silanes, stannanes, boronic as well arenes, furnishes highly substituted cyclopropanes. transformation may be performed in the presence air moisture 0.5 mol % a benzothiazinoquinoxaline organophotocatalyst. Mechanistic investigations, involving Stern–Volmer quenching, quantum yield determination, deuteration experiments, are carried out, catalytic cycle for discussed.

Language: Английский

Citations

52
Electrochemically Driven Hydrogen Atom Transfer Catalysis: A Tool for C(sp3)/Si–H Functionalization and Hydrofunctionalization of Alkenes DOI Creative Commons
Sheng Zhang, Michael Findlater

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(13), P. 8731 - 8751

Published: June 16, 2023

Electrochemically driven hydrogen atom transfer (HAT) catalysis provides a complementary approach for the transformation of redox-inactive substrates that would be inaccessible to conventional electron (ET) catalysis. Moreover, electrochemically HAT could promote organic transformations with either abstraction or donation as key step. It versatile and effective tool direct functionalization C(sp3)–H/Si–H bonds hydrofunctionalization alkenes. Despite these attractive properties, has been largely overlooked due lack understanding both catalytic mechanism how catalyst selection should occur. In this Review, we give an overview applications in The mechanistic pathways, physical properties mediators, state-of-the-art examples are described discussed.

Language: Английский

Citations

50
Alcohols as Substrates in Transition-Metal-Catalyzed Arylation, Alkylation, and Related Reactions DOI

Adam Cook,

Stephen G. Newman

Chemical Reviews, Journal Year: 2024, Volume and Issue: 124(9), P. 6078 - 6144

Published: April 17, 2024

Alcohols are abundant and attractive feedstock molecules for organic synthesis. Many methods their functionalization require them to first be converted into a more activated derivative, while recent years have seen vast increase in the number of complexity-building transformations that directly harness unprotected alcohols. This Review discusses how transition metal catalysis can used toward this goal. These broadly classified three categories. Deoxygenative functionalizations, representing derivatization C–O bond, enable alcohol act as leaving group formation new C–C bonds. Etherifications, characterized by O–H represent classical reactivity has been modernized include mild reaction conditions, diverse partners, high selectivities. Lastly, chain reactions described, wherein acts mediator formal C–H alkyl backbone. Each these classes transformation will discussed context intermolecular arylation, alkylation, related reactions, illustrating alcohols harnessed

Language: Английский

Citations

39
Co-Catalyzed Hydrofluorination of Alkenes: Photocatalytic Method Development and Electroanalytical Mechanistic Investigation DOI
Jinjian Liu, Jian Rong, Devin Wood

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(7), P. 4380 - 4392

Published: Feb. 1, 2024

The hydrofluorination of alkenes represents an attractive strategy for the synthesis aliphatic fluorides. This approach provides a direct means to form C(sp3)–F bonds selectively from readily available alkenes. Nonetheless, conducting using nucleophilic fluorine sources poses significant challenges due low acidity and high toxicity associated with HF poor nucleophilicity fluoride. In this study, we present new Co(salen)-catalyzed simple utilizing Et3N·3HF as sole source both hydrogen fluorine. process operates via photoredox-mediated polar-radical-polar crossover mechanism. We also demonstrated versatility method by effectively converting diverse array activated varying degrees substitution into hydrofluorinated products. Furthermore, successfully applied methodology 18F-hydrofluorination reactions, enabling introduction 18F potential radiopharmaceuticals. Our mechanistic investigations, conducted rotating disk electrode voltammetry DFT calculations, unveiled involvement carbocation CoIV–alkyl species viable intermediates during fluorination step, contribution each pathway depends on structure starting alkene.

Language: Английский

Citations

31
A Dual Cobalt and Photoredox Catalysis for Hydrohalogenation of Alkenes DOI

Shotaro Shibutani,

Kazunori Nagao, Hirohisa Ohmiya

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(7), P. 4375 - 4379

Published: Feb. 1, 2024

We demonstrate hydrohalogenation of aliphatic alkenes with collidine·HX salts through dual photoredox/cobalt catalysis. The catalysis enables conversion a proton and halide anion from salt to nucleophilic hydrogen radical equivalent an electrophilic halogen delivery them alkene moiety. This protocol allows for introduction fluorine, chlorine, bromine, or iodine atom alkene, producing highly functionalized alkyl halides.

Language: Английский

Citations

27
Engaging Alkenes in Metallaphotoredox: A Triple Catalytic, Radical Sorting Approach to Olefin-Alcohol Cross-Coupling DOI
Qinyan Cai, Iona M. McWhinnie, Nathan W. Dow

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(18), P. 12300 - 12309

Published: April 24, 2024

Metallaphotoredox cross-coupling is a well-established strategy for generating clinically privileged aliphatic scaffolds via single-electron reactivity. Correspondingly, expanding metallaphotoredox to encompass new C(

Language: Английский

Citations

24
Photo‐ and Cobalt‐Catalyzed Synthesis of Heterocycles via Cycloisomerization of Unactivated Olefins DOI Creative Commons
Henry Lindner, Willi M. Amberg, Tristano C. Martini

et al.

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(19)

Published: Feb. 28, 2024

Abstract We report a general, intramolecular cycloisomerization of unactivated olefins with pendant nucleophiles. The reaction proceeds under mild conditions and tolerates ethers, esters, protected amines, acetals, pyrazoles, carbamates, arenes. It is amenable to N ‐, O as well C ‐nucleophiles, yielding number different heterocycles including, but not limited to, pyrrolidines, piperidines, oxazolidinones, lactones. Use both benzothiazinoquinoxaline organophotocatalyst Co‐salen catalyst obviates the need for stoichiometric oxidant or reductant. showcase utility protocol in late‐stage drug diversification synthesis several small natural products.

Language: Английский

Citations

20
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

48