Stable Meisenheimer Complexes as Powerful Photoreductants Readily Obtained from Aza‐Heteroaromatic Compounds DOI Creative Commons
Francesco Calogero,

Leonie Wilczek,

Emanuele Pinosa

et al.

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(44)

Published: July 30, 2024

Abstract Excited states of radical anions derived from the photoreduction stable organic molecules are suggested to serve as potent reductants. However, excited these species too short‐lived allow bimolecular quenching processes. Recently, singlet state Meisenheimer complexes, which possess a long‐lived state, was identified competent for reduction challenging substrates (−2.63 V vs. SCE, saturated calomel electrode). To produce reasonably and simply accessible different addition n BuLi readily available aromatic heterocycles investigated, photoreactivity generated studied. In this paper, we present straightforward preparation family powerful photoreductants (*E ox < −3 SCE in their states, determined by DFT time‐dependent TD‐DFT calculations; DFT, density functional theory) that can induce dehalogenation electron‐rich aryl chlorides form C−C bond through cyclization. Photophysical analyses computational studies combination with experimental mechanistic investigations demonstrate ability adduct act strong electron donor under visible light irradiation.

Language: Английский

A guide to troubleshooting metal sacrificial anodes for organic electrosynthesis DOI Creative Commons
Skyler D. Ware,

Wendy Zhang,

Weiyang Guan

et al.

Chemical Science, Journal Year: 2024, Volume and Issue: 15(16), P. 5814 - 5831

Published: Jan. 1, 2024

Sacrificial anodes enable reductive electrosynthesis but can inadvertently limit the conditions compatible with organic reactions. Addressing challenges that arise at sacrificial improve yields and streamline reaction optimization.

Language: Английский

Citations

5
Zinc and manganese redox potentials in organic solvents and their influence on nickel-catalyzed cross-electrophile coupling DOI Creative Commons
Zhi-Ming Su, Ruohan Deng, Shannon S. Stahl

et al.

Published: May 27, 2024

Zinc and manganese are widely used as reductants in synthetic methods, such nickel-catalyzed cross-electrophile coupling (XEC) reactions, but their redox potentials unknown organic solvents. Here, we show how open-circuit potential measurements may be to determine the thermodynamic of Zn Mn different solvents presence common reaction additives. The impact these is analyzed for a pair Ni-catalyzed each showing preference one two reductants. N-alkyl-2,4,6-triphenylpyridinium reagents (Katritzky salts) with aryl halides then compared under chemical conditions, using or reductants, electrochemical performed at applied corresponding reduction optimized achieve maximum yield. collective results illuminate important role reductant XEC reactions.

Language: Английский

Citations

5
Metallaphotoredox‐Catalyzed Enantioselective Cross‐Electrophile Coupling Using Alcohols as Reducing Agents DOI
Zhilong Li,

Leitao Huan,

Jian Li

et al.

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(31)

Published: June 1, 2023

The cross-electrophile coupling (XEC) represents a powerful strategy for C-C bond formation. However, controlling the enantioselectivity in these processes remains challenge. Here, we report an unprecedented enantioselective XEC of α-amino acid derivatives with aryl bromides, enabled by alcohols as reducing agents via Ni/photoredox catalysis. This mechanistically distinct approach exploits ability photocatalytically generated α-hydroxyalkyl radicals to convert alkyl electrophiles corresponding that are then enantioselectively coupled bromides. readily scalable protocol allows modular access valuable enantioenriched benzylic amines from abundant and inexpensive precursors, is applicable late-stage diversification broad functional group tolerance. Mechanistic studies rationalize versatility this alcohol-based reactivity radical generation subsequent asymmetric cross-coupling. We expect cross-coupling will render general platform development appealing yet challenging XECs.

Language: Английский

Citations

13
Ligand–Metal Cooperation Enables Net Ring-Opening C–C Activation/Difunctionalization of Cyclopropyl Ketones DOI
Michael M. Gilbert, Michael J. Trenerry,

Victoria Longley

et al.

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(17), P. 11277 - 11290

Published: Aug. 11, 2023

Reactions that cleave C–C bonds and enable functionalization at both carbon sites are powerful strategic tools in synthetic chemistry. Stereodefined cyclopropyl ketones have become readily available would be an ideal source of 3-carbon fragments, but general approaches to net activation/difunctionalization unknown. Herein, we demonstrate the cross-coupling with organozinc reagents chlorotrimethylsilane form 1,3-difunctionalized, ring-opened products. A combination experimental theoretical studies rules out more established mechanisms sheds light on how cooperation between redox-active terpyridine (tpy) ligand nickel atom enables bond activation step. The reduced (tpy·–)NiI species activates via a concerted asynchronous ring-opening transition state. resulting alkylnickel(II) intermediate can then engaged by aryl, alkenyl, alkylzinc furnish cross-coupled This allows quick access products difficult make conjugate addition methods, such as β-allylated β -benzylated enol ethers. utility this approach is demonstrated synthesis key (±)-taiwaniaquinol B total prostaglandin D1.

Language: Английский

Citations

13
Palladium(I)-Iodide-Catalyzed Deoxygenative Heck Reaction of Vinyl Triflates: A Formate-Mediated Cross-Electrophile Reductive Coupling with cine-Substitution DOI
Yu-Hsiang Chang, Weijia Shen, Jonathan Z. Shezaf

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(42), P. 22890 - 22895

Published: Oct. 16, 2023

The first deoxygenative Heck reactions are described, as illustrated by formate-mediated

Language: Английский

Citations

12
Bis(pinacolato)diboron‐Enabled Ni‐Catalyzed Reductive Arylation/Vinylation of Alkyl Electrophiles DOI Creative Commons
Deli Sun, Yuxin Gong,

Yu Wu

et al.

Advanced Science, Journal Year: 2024, Volume and Issue: 11(31)

Published: June 17, 2024

Abstract Herein, the use of economically and environmentally friendly bis(pinacolato)diboron (B 2 Pin ) is described as a non‐metallic reductant in mediating Ni‐catalyzed C(sp 3 )–C(sp reductive cross‐coupling alkyl electrophiles with aryl/vinyl halides. This method exhibits excellent suitability for heteroaryl halides halides/Katritzky salts. The present study compatible an situ halogenation alcohol method, allowing selective mono‐functionalization diols bio‐relevant alcohols (e.g., carbohydrates). B shows potential easy scalability without introducing additional metal impurities into products. It observed first time realm cross‐electrophile coupling chemistry that can sever to reduce Ni II 0 . mechanistic insight may inspire development new bond‐forming methodologies otherwise be difficult achieve reductant.

Language: Английский

Citations

4
Triaminoalkenes Derived from Cyclic (Alkyl)(amino)carbenes with a 1,1′‐Ferrocenylene Backbone and N‐Heterocyclic Carbenes: fcCAAC–NHC Heterodimers DOI Creative Commons
Suman Yadav,

Clemens Bruhn,

Clemens Lücke

et al.

ChemistryOpen, Journal Year: 2025, Volume and Issue: unknown

Published: April 14, 2025

The study addresses triaminoalkenes derived from [3]ferrocenophane‐type cyclic (alkyl)(amino)carbenes (fcCAACs) fc(CPh 2 CNR) (fc = 1,1′‐ferrocenylene) and N ‐heterocyclic carbenes (NHCs). Stable target compounds are obtained in good yields as crystalline solids by the combination of [fc(CPh CHNMe)][BF 4 ] with , ′‐dimethylimidazolin‐2‐ylidene CHN‐ p ‐C 6 H ‐ t Bu)](OTf) 1,3,4,5‐tetramethylimidazolin‐2‐ylidene, respectively, followed treatment resulting addition product KN(SiMe 3 ) . Due to presence a triaminoethene unit ferrocene moiety, four redox states expected for such fcCAAC–NHC heterodimers, viz., electroneutral, mono‐, di‐, tricationic. An investigation their behavior electrochemical methods (cyclic voltammetry differential pulse voltammetry) has revealed that these undergo two consecutive one‐electron oxidations, poor stability dicationic species solution preventing an observation tricationic state. A density functional theory (DFT) shows highest occupied molecular orbital (HOMO) is localized on C CN atom, which, agreement electron paramagnetic resonance results, site first oxidation. second oxidation mainly involves Fe where HOMO−1 localized, triplet ground state composed, approximation, carbon‐centered iron‐centered radical.

Language: Английский

Citations

0
Translation of Nickel-Catalyzed C(sp2)–C(sp3) Cross-Electrophile Coupling to Non-Amide Solvents DOI
Brett D. Akana-Schneider, Julianna M. Mouat, Sisi Zhang

et al.

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: April 14, 2025

The cross-electrophile coupling of organobromides is widely utilized in organic synthesis but generally requires undesirable amide solvents (e.g., DMF, DMA, and NMP). We report that the combination a strongly donating, bidentate nitrogen ligand, LiI, 4-picoline enables variety alcohol, ester, ethereal at up to 50 g scale. An improved optimal 4,4'-bis(dimethylamino)-2,2'-bipyridine, also reported on basis reductive homocoupling 4-dimethylamino-2-chloropyridine.

Language: Английский

Citations

0
Formate-Mediated C–C Coupling of Aryl/Vinyl Halides and Triflates: Carbonyl Arylation and Reductive Cross-Coupling DOI
Yu-Hsiang Chang, Yoon Cho, Weijia Shen

et al.

ACS Catalysis, Journal Year: 2025, Volume and Issue: unknown, P. 8274 - 8283

Published: May 2, 2025

Language: Английский

Citations

0
Development of Photoredox Cross-Electrophile Coupling of Strained Heterocycles with Aryl Bromides Using High-Throughput Experimentation for Library Construction DOI
Yukiko Mori,

Mutsuyo Hayashi,

Ryuma Sato

et al.

Organic Letters, Journal Year: 2023, Volume and Issue: 25(30), P. 5569 - 5573

Published: July 24, 2023

Microscale high-throughput experimentation was used to develop a photoredox-assisted reductive cross-coupling reaction of aryl halides with strained aliphatic heterocycles facilitated via ring-opening reaction. This methodology found be applicable medicinally relevant substrates including Boc-protected and (hetero)aryl bromides for compound library construction parallel medicinal chemistry. Furthermore, the coupling reactions were shown scalable gram scale by continuous flow A possible mechanism is also discussed.

Language: Английский

Citations

8