scholarly journals Non-Innocent Radical Ion Intermediates in Photoredox Catalysis: Parallel Reduction Modes Enable Coupling of Diverse Aryl Chlorides

2021 ◽  
Author(s):  
Alyah Chmiel ◽  
Oliver P. Williams ◽  
Colleen Chernowsky ◽  
Charles Yeung ◽  
Zachary Wickens
Keyword(s):  
Radical Anion ◽  
Sodium Formate ◽  
Coupling Reactions ◽  
Aryl Radical ◽  
Aryl Chloride ◽  
Aryl Chlorides ◽  
Radical Coupling ◽  
Substrate Reduction ◽  
Photocatalytic System

We describe a photocatalytic system that elicits potent photoreductant activity from conventional photocatalysts by leveraging radical anion intermediates generated <i>in situ</i>. The combination of isophthalonitrile and sodium formate promotes diverse aryl radical coupling reactions from abundant but difficult to reduce aryl chloride substrates. Mechanistic studies reveal two parallel pathways for substrate reduction both enabled by a key terminal reductant byproduct, carbon dioxide radical anion.

scholarly journals Non-Innocent Radical Ion Intermediates in Photoredox Catalysis: Parallel Reduction Modes Enable Coupling of Diverse Aryl Chlorides

2021 ◽  
Author(s):  
Alyah Chmiel ◽  
Oliver P. Williams ◽  
Colleen Chernowsky ◽  
Charles Yeung ◽  
Zachary Wickens
Keyword(s):  
Radical Anion ◽  
Sodium Formate ◽  
Coupling Reactions ◽  
Aryl Radical ◽  
Aryl Chloride ◽  
Aryl Chlorides ◽  
Radical Coupling ◽  
Substrate Reduction ◽  
Photocatalytic System

We describe a photocatalytic system that elicits potent photoreductant activity from conventional photocatalysts by leveraging radical anion intermediates generated <i>in situ</i>. The combination of isophthalonitrile and sodium formate promotes diverse aryl radical coupling reactions from abundant but difficult to reduce aryl chloride substrates. Mechanistic studies reveal two parallel pathways for substrate reduction both enabled by a key terminal reductant byproduct, carbon dioxide radical anion.

scholarly journals Organophotocatalytic selective deuterodehalogenation of aryl or alkyl chlorides

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yanjun Li ◽  
Ziqi Ye ◽  
Yu-Mei Lin ◽  
Yan Liu ◽  
Yumeng Zhang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Sodium Formate ◽  
Bioactive Molecules ◽  
Co Catalyst ◽  
Aryl Chlorides ◽  
Aryl Amine ◽  
Drug Molecules ◽  
Photocatalytic System ◽  
Site Selective ◽  
Environmentally Friendly Method

AbstractDevelopment of practical deuteration reactions is highly valuable for organic synthesis, analytic chemistry and pharmaceutic chemistry. Deuterodehalogenation of organic chlorides tends to be an attractive strategy but remains a challenging task. We here develop a photocatalytic system consisting of an aryl-amine photocatalyst and a disulfide co-catalyst in the presence of sodium formate as an electron and hydrogen donor. Accordingly, many aryl chlorides, alkyl chlorides, and other halides are converted to deuterated products at room temperature in air (>90 examples, up to 99% D-incorporation). The mechanistic studies reveal that the aryl amine serves as reducing photoredox catalyst to initiate cleavage of the C-Cl bond, at the same time as energy transfer catalyst to induce homolysis of the disulfide for consequent deuterium transfer process. This economic and environmentally-friendly method can be used for site-selective D-labeling of a number of bioactive molecules and direct H/D exchange of some drug molecules.

Recent Developments in Transition-Metal-Free Functionalization and Derivatization Reactions of Pyridines

Synlett ◽  
2020 ◽  
Author(s):  
Lei Jiao ◽  
Fei-Yu Zhou
Keyword(s):  
Transition Metal ◽  
Structural Motif ◽  
Metal Exchange ◽  
Coupling Reactions ◽  
Phosphonium Salts ◽  
Metal Free ◽  
Radical Coupling ◽  
In Situ Activation ◽  
Recent Developments

AbstractPyridine is an important structural motif that is prevalent in natural products, drugs, and materials. Methods that functionalize and derivatize pyridines have gained significant attention. Recently, a large number of transition-metal-free reactions have been developed. In this review, we provide a brief summary of recent advances in transition-metal-free functionalization and derivatization reactions of pyridines, categorized according to their reaction modes.1 Introduction2 Metalated Pyridines as Nucleophiles2.1 Deprotonation2.2 Halogen–Metal exchange3 Activated Pyridines as Electrophiles3.1 Asymmetric 2-Allylation by Chiral Phosphite Catalysis3.2 Activation of Pyridines by a Bifunctional Activating Group3.3 Alkylation of Pyridines by 1,2-Migration3.4 Alkylation of Pyridines by [3+2] Addition3.5 Pyridine Derivatization by Catalytic In Situ Activation Strategies3.6 Reactions via Heterocyclic Phosphonium Salts4 Radical Reactions for Pyridine Functionalization4.1 Pyridine Functionalization through Radical Addition Reactions4.2 Pyridine Functionalization through Radical–Radical Coupling Reactions5 Derivatization of Pyridines through the Formation of Meisenheimer-Type Pyridyl Anions6 Conclusion

ChemInform Abstract: One-Pot Negishi Cross-Coupling Reactions of in situ Generated Zinc Reagents with Aryl Chlorides, Bromides, and Triflates.

ChemInform ◽  
2009 ◽  
Vol 40 (5) ◽  
Author(s):  
Shohei Sase ◽  
Milica Jaric ◽  
Albrecht Metzger ◽  
Vladimir Malakhov ◽  
Paul Knochel
Keyword(s):  
Cross Coupling ◽  
Coupling Reactions ◽  
One Pot ◽  
Aryl Chlorides ◽  
Cross Coupling Reactions

scholarly journals Pyridylphosphonium Salts as Alternatives to Cyanopyridines in Radical-Radical Coupling Reactions

2021 ◽  
Author(s):  
Jacob W. Greenwood ◽  
Andrew McNally
Keyword(s):  
Late Stage ◽  
Radical Anion ◽  
Cyano Group ◽  
Radical Anions ◽  
Coupling Reactions ◽  
Photoredox Catalysis ◽  
Phosphonium Salts ◽  
Radical Coupling

Radical couplings of cyanopyridine radical anions represent a valuable technology for functionalizing pyridines, which are prevalent throughout pharmaceuticals, agrochemicals, and materials. Installing the cyano group, necessary for radical anion stabilization, is challenging and limits the use of this chemistry to simple cyanopyridines. We discovered that pyridyl phosphonium salts, installed regioselectively from C-H precursors, are useful alternatives to cyanopyridines in radical-radical coupling reactions, expanding the scope of this reaction manifold to complex pyridines. Methods for both alkylation and amination of pyridines mediated by photoredox catalysis are described. Additionally, we demonstrate late-stage functionalization of pharmaceuticals, highlighting an advantage of pyridyl phosphonium salts over cyanopyridines.

One-Pot Negishi Cross-Coupling Reactions of In Situ Generated Zinc Reagents with Aryl Chlorides, Bromides, and Triflates

2008 ◽  
Vol 73 (18) ◽  
pp. 7380-7382 ◽  
Author(s):  
Shohei Sase ◽  
Milica Jaric ◽  
Albrecht Metzger ◽  
Vladimir Malakhov ◽  
Paul Knochel
Keyword(s):  
Cross Coupling ◽  
Coupling Reactions ◽  
One Pot ◽  
Aryl Chlorides ◽  
Cross Coupling Reactions

scholarly journals Pyridylphosphonium Salts as Alternatives to Cyanopyridines in Radical-Radical Coupling Reactions

2021 ◽  
Author(s):  
Jacob W. Greenwood ◽  
Andrew McNally
Keyword(s):  
Late Stage ◽  
Radical Anion ◽  
Cyano Group ◽  
Radical Anions ◽  
Coupling Reactions ◽  
Photoredox Catalysis ◽  
Phosphonium Salts ◽  
Radical Coupling

Radical couplings of cyanopyridine radical anions represent a valuable technology for functionalizing pyridines, which are prevalent throughout pharmaceuticals, agrochemicals, and materials. Installing the cyano group, necessary for radical anion stabilization, is challenging and limits the use of this chemistry to simple cyanopyridines. We discovered that pyridyl phosphonium salts, installed regioselectively from C-H precursors, are useful alternatives to cyanopyridines in radical-radical coupling reactions, expanding the scope of this reaction manifold to complex pyridines. Methods for both alkylation and amination of pyridines mediated by photoredox catalysis are described. Additionally, we demonstrate late-stage functionalization of pharmaceuticals, highlighting an advantage of pyridyl phosphonium salts over cyanopyridines.

Synthesis, Characterization and Catalytic Utilization of a Ferrocene Diamidodiphosphane

2007 ◽  
Vol 72 (4) ◽  
pp. 453-467 ◽  
Author(s):  
Petr Štěpnička ◽  
Jiří Schulz ◽  
Ivana Císařová ◽  
Karla Fejfarová
Keyword(s):  
Phenylboronic Acid ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Aryl Halides ◽  
Coupling Reactions ◽  
Aryl Chlorides ◽  
Highly Active ◽  
Aryl Bromides ◽  
Cross Coupling Reaction

Amidation of 1'-(diphenylphosphanyl)ferrocene-1-carboxylic acid (Hdpf) with ethane-1,2-diamine afforded N,N'-ethylenebis[1'-(diphenylphosphanyl)ferrocene-1-carboxamide] (1), which was isolated in free and solvated form, 1·2AcOH. Both 1 and Hdpf were further converted to their respective phosphane sulfides, 2·2AcOH and 3 that were structurally characterized. Testing of the amidophosphane ligands in Suzuki-Miyaura cross-coupling reaction between phenylboronic acid and various aryl halides revealed that catalyst formed in situ from 1 and palladium(II) acetate is highly active in coupling reactions of aryl bromides whilst the corresponding aryl chlorides showed no or only poor conversions. The catalyst based on 2·2AcOH gave markedly lower yields of the coupling products.

Chiral Mn(III) Salen Complex Immobilized on CuFe2O4@SiO2-NH2 NPs: A Cheap and Efficient Catalyst for N-arylation of Aryl Halides and Phenylboronic Acid Under Mild Conditions

2020 ◽  
Vol 17 (11) ◽  
pp. 857-863
Author(s):  
Mohammad Ali Nasseri ◽  
Seyyedeh Ameneh Alavi ◽  
Milad Kazemnejadi ◽  
Ali Allahresani
Keyword(s):  
Phenylboronic Acid ◽  
Significant Loss ◽  
Aryl Halides ◽  
Coupling Reactions ◽  
Efficient Catalyst ◽  
Aryl Chlorides ◽  
Mild Conditions ◽  
Cross Coupling Reactions ◽  
Salen Complex ◽  
Ft Ir

A convenient and efficient chiral CuFe2O4@SiO2-Mn(III) Ch.salen nanocatalyst has been developed for the C-N cross-coupling reactions of aryl halides/ phenylboronic acid with N-heterocyclic compounds in water and/or DMSO under mild conditions. The catalyst could be applied for the N-arylation of a variety of nitrogen-containing heterocycles with aryl chlorides, bromides, iodides and phenylboronic acid under mild conditions. Moderate to good yields were achieved for all substrates. The structure of catalyst was characterized using various techniques including FT-IR, FE-SEM, EDX, XRD, TEM and TGA. The catalyst can be simply recovered and reused for several times without significant loss of activity.

Insertion Reaction of 2-Halo-N-allylanilines with K2S Involving Trisulfur Radical Anion: Synthesis of Benzothiazole Derivatives under Transition-Metal-Free Conditions

Synthesis ◽  
2020 ◽  
Author(s):  
Yan-Wei Zhao ◽  
Shun-Yi Wang ◽  
Xin-Yu Liu ◽  
Tian Jiang ◽  
Weidong Rao
Keyword(s):  
Transition Metal ◽  
Radical Anion ◽  
Radical Cyclization ◽  
Transition Metal Catalysis ◽  
Insertion Reaction ◽  
Metal Catalysis ◽  
Metal Free ◽  
Benzothiazole Derivatives

AbstractA synthesis of benzothiazole derivatives through the reaction of 2-halo-N-allylanilines with K2S in DMF is developed. The trisulfur radical anion S3·–, which is generated in situ from K2S in DMF, initiates the reaction without transition-metal catalysis or other additives. In addition, two C–S bonds are formed and heteroaromatization of benzothiazole is triggered by radical cyclization and H-shift.

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