Photochemical Metal‐Hydride Hydrogen Atom Transfer Mediated Radical Hydrofunctionalization of Dienes and Allenes DOI

Huaipu Yan,

Jing‐Ran Shan, Lei Shi

et al.

ChemCatChem, Journal Year: 2023, Volume and Issue: 16(2)

Published: Nov. 17, 2023

The metal-hydride hydrogen atom transfer (MHAT) method is widely recognized as a powerful technique for functionalizing alkenes. However, its application in the functionalization of industrial feedstock dienes and allenes relatively rare due to challenges related chemo-selectivity. In recent studies, Co-porphines have been identified highly efficient catalysts under photoirradiation MHAT, demonstrating an exceptional level chemoselectivity allenes, while disregarding other simple olefins present. This novel enables selective reductive coupling pyridines with allylation aldehydes by combination Ti catalysis. Mechanistic studies density functional theory (DFT) calculations support idea that non-reversible atoms from cobalt hydride leading generation allyl radicals, key step catalytic cycle.

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

57
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

56
Hantzsch Esters Enabled [2π+2σ] Cycloadditions of Bicyclo [1.1.0] butanes and Alkenes under Photo Conditions DOI

Huaipu Yan,

Yonghong Liu, Xiao Feng

et al.

Organic Letters, Journal Year: 2023, Volume and Issue: 25(45), P. 8116 - 8120

Published: Nov. 8, 2023

Hantzsch esters (HEs) are widely recognized as sources of hydride ions (H-) and sacrificial electron donors in their ground state. Here, we report the application HE a mediator [2π+2σ] cycloaddition bicyclo[1.1.0]butanes (BCBs) with alkenes under photo conditions. Through this strategy, various substituted bicyclo[2.1.1]hexanes can be efficiently prepared.

Language: Английский

Citations

50
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

25
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

19
Photocatalytic Metal Hydride Hydrogen Atom Transfer Mediated Allene Functionalization by Cobalt and Titanium Dual Catalysis DOI

Huaipu Yan,

Qian Liao, Yuqing Chen

et al.

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(24)

Published: April 12, 2023

Catalytic metal hydride hydrogen atom transfer (MHAT) reactions have proven to be a powerful method for alkene functionalization. This work reports the discovery of Co-porphines as highly efficient MHAT catalysts with loading only 0.01 mol % unprecedented chemoselective allene functionalization under photoirradiation. Moreover, newly developed bimetallic strategy by combination photo Co-MHAT and Ti catalysis enabled successful carbonyl allylation wide range amino, oxy, thio, aryl, alkyl-allenes providing expedient access valuable β-functionalized homoallylic alcohols in over 100 examples exceptional regio- diastereoselectivity. Mechanism studies DFT calculations supported that selectively transferring atoms from cobalt allenes generating allyl radicals is key step catalytic cycle.

Language: Английский

Citations

27
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

Citations

23
Visible light catalyzed arylsilylation of alkenes to construct silicon-containing 1,1-diaryl moieties DOI
Jia Cao, Liuzhou Gao, Guoqiang Wang

et al.

Green Chemistry, Journal Year: 2024, Volume and Issue: 26(8), P. 4785 - 4791

Published: Jan. 1, 2024

We have developed an efficient photocatalyzed arylsilylation of alkenes, utilizing silylboranes and (hetero)aryl nitriles in the presence base photocatalyst.

Language: Английский

Citations

8
Dual‐Catalysed Intermolecular Reductive Coupling of Dienes and Ketones** DOI Creative Commons

Victor J. Mayerhofer,

Martina Lippolis, Christopher J. Teskey

et al.

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 63(2)

Published: Nov. 10, 2023

Abstract We report a mild, catalytic method for the intermolecular reductive coupling of feedstock dienes and styrenes with ketones. Our conditions allow concomitant formation cobalt hydride species single‐electron reduction Subsequent selective hydrogen‐atom transfer from generates an allylic radical which can selectively couple persistent radical‐anion ketone. This radical‐radical negates unfavourable steric interactions ionic pathways avoids unstable alkoxy previous olefin‐carbonyl couplings, were limited, as result, to aldehydes. Applications this novel straightforward approach include efficient synthesis drug molecules, key intermediates in site‐selective late‐stage functionalisation.

Language: Английский

Citations

20
Site‐Selective Pyridination of Benzylic and Allylic C−H bonds via Radical‐Radical Cross‐Coupling DOI

Junjie Chen,

Zhan‐Jie Wang,

Huan‐Ming Huang

et al.

Advanced Synthesis & Catalysis, Journal Year: 2024, Volume and Issue: 366(6), P. 1306 - 1314

Published: Jan. 26, 2024

Abstract Herein, we report a modular photocatalytic platform for the site‐selective pyridination of saturated hydrocarbon compounds employing organic photoredox catalysis to forge new carbon‐carbon bonds. The C−H could couple benzylic/allylic bonds with pyridylphosphonium salts, which installed directly and regioselectively from heteroarenes through radical‐radical cross coupling mechanism. This synthetic methodology tolerate variety functional groups, complex heteroarenes, even late‐stage functionalization pharmaceuticals selectively.

Language: Английский

Citations

5