Water as an Electron Donor for Cross-Electrophile Coupling Reactions.

Cross-electrophile coupling (XEC) reactions are considered to be among the most fundamental construction of carbon-carbon bonds in organic chemistry. Traditionally, stoichiometric reductants, including metallic and organic reagents, are required to promote these conversions, resulting in significant waste that contributes to environmental pollution and increased disposal costs. In this study, we report a divided electrochemical synthesis-based cross-coupling platform in which HO is oxidized at the anode surface to generate electrons that produce a lower oxidation state nickel catalyst on the cathode surface, enabling XEC reactions without the need for metallic or organic reagents.

Catalytic Quantities of Inorganic Salt Promote an Electron Donor-Acceptor Complex to Achieve Defluorinated Cycloaddition.

A novel strategy has been developed for synthesizing α-naphthols by photoinduced electron donor-acceptor (EDA) complexes. The method has mild reaction conditions, requires no external oxidants or reducing agents, and shows a broad substrate scope. Notably, the activation mode using catalytic quantities of inorganic salts as the EDA donor has scarcely been reported before.

Redox-Neutral Carboxylation of Benzylic Tertiary C-H Bonds with Carbon Dioxide.

The direct catalytic carboxylation of benzylic tertiary C-H bonds with CO for the synthesis of all-carbon quaternary carboxylic acids represents a significant challenge. Here, we present a redox-neutral approach to address this difficulty by leveraging the synergistic interplay between photocatalysis and cascade hydrogen abstraction cycles. Remarkably, this strategy eliminates the need for sacrificial electron donors, electron acceptors, or stoichiometric additives, offering enhanced atom economy and environmental sustainability.

Deconstructive Carboxylation of Activated Alkenes with Carbon Dioxide.

Carboxylation with carbon dioxide (CO ) represents one notable methodology to produce carboxylic acids. In contrast to carbon-heteroatom bonds, carbon-carbon bond cleavage for carboxylation with CO is far more challenging due to their inherent and less favorable orbital directionality for interacting with transition metals. Here we report a photocatalytic protocol for the deconstructive carboxylation of alkenes with CO to generate carboxylic acids in the absence of transition metals.

Aroyl Fluorides as Bifunctional Reagents for Dearomatizing Fluoroaroylation of Benzofurans.

The 2,3-dihydrobenzofuran scaffold is widely found in natural products and biologically active compounds. Herein, dearomatizing 2,3-fluoroaroylation of benzofurans with aroyl fluorides as bifunctional reagents to access 2,3-difunctionalized dihydrobenzofurans is reported. The reaction that occurs by cooperative NHC/photoredox catalysis provides 3-aroyl-2-fluoro-2,3-dihydrobenzofurans with moderate to good yield and high diastereoselectivity.

[Essence of 's clinical features on acupuncture and moxibustion].

To summarize 's treatment ideas and clinical features. applies meridian syndrome differentiation to the diagnosis and treatment of diseases; advocates that prevention and treatment of diseases should be regulated mind firstly; applies transcranial repetitive acupuncture combined modern cerebral cortex function positioning; emphasizes the application of multiple acupuncture methods and manipulation, and includes the meridian penetrating needling method, the flat needling and penetrating needling method, and the stagnant needle lifting method, pays attention to the importance of achieving and manipulation for the effect.

Benzylic C-H acylation by cooperative NHC and photoredox catalysis.

Methods that enable site selective acylation of sp C-H bonds in complex organic molecules are not well explored, particularly if compared with analogous transformations of aromatic and vinylic sp C-H bonds. We report herein a direct acylation of benzylic C-H bonds by merging N-heterocyclic carbene (NHC) and photoredox catalysis. The method allows the preparation of a diverse range of benzylic ketones with good functional group tolerance under mild conditions.

Cooperative NHC and Photoredox Catalysis for the Synthesis of β-Trifluoromethylated Alkyl Aryl Ketones.

Despite the great potential of radical chemistry in organic synthesis, N-heterocyclic carbene (NHC)-catalyzed reactions involving radical intermediates are not well explored. This communication reports the three-component coupling of aroyl fluorides, styrenes and the Langlois reagent (CF SO Na) to give various β-trifluoromethylated alkyl aryl ketones with good functional group tolerance in moderate to high yields by cooperative photoredox/NHC catalysis. The alkene acyltrifluoromethylation proceeds via radical/radical cross coupling of ketyl radicals with benzylic C-radicals.

Boosting Electrochemical Reduction of CO at a Low Overpotential by Amorphous Ag-Bi-S-O Decorated Bi Nanocrystals.

Bimetal-S-O composites have been rarely researched in electrochemical reduction of CO . Now, an amorphous Ag-Bi-S-O decorated Bi catalyst derived from Ag BiS O nanorods by electrochemical pre-treatment was used for catalyzing eCO RR, which exhibited a formate FE of 94.3 % with a formate partial current density of 12.

Photocarboxylation of Benzylic C-H Bonds.

The carboxylation of sp-hybridized C-H bonds with CO is a challenging transformation. Herein, we report a visible-light-mediated carboxylation of benzylic C-H bonds with CO into 2-arylpropionic acids under metal-free conditions. Photo-oxidized triisopropylsilanethiol was used as the hydrogen atom transfer catalyst to afford a benzylic radical that accepts an electron from the reduced form of 2,3,4,6-tetra(9H-carbazol-9-yl)-5-(1-phenylethyl)benzonitrile generated .

Site-Selective, Remote sp C-H Carboxylation Enabled by the Merger of Photoredox and Nickel Catalysis.

A photoinduced carboxylation of alkyl halides with CO at remote sp C-H sites enabled by the merger of photoredox and Ni catalysis is described. This protocol features a predictable reactivity and site selectivity that can be modulated by the ligand backbone. Preliminary studies reinforce a rationale based on a dynamic displacement of the catalyst throughout the alkyl side chain.

Controllable Isomerization of Alkenes by Dual Visible-Light-Cobalt Catalysis.

We report herein that thermodynamic and kinetic isomerization of alkenes can be accomplished by the combination of visible light with Co catalysis. Utilizing Xantphos as the ligand, the most stable isomers are obtained, while isomerizing terminal alkenes over one position can be selectively controlled by using DPEphos as the ligand. The presence of the donor-acceptor dye 4CzIPN accelerates the reaction further.

Ligand-Controlled Regioselective Hydrocarboxylation of Styrenes with CO by Combining Visible Light and Nickel Catalysis.

The ligand-controlled Markovnikov and anti-Markovnikov hydrocarboxylation of styrenes with atmospheric pressure of CO at room temperature using dual visible-light-nickel catalysis has been developed. In the presence of neocuproine as ligand, the Markovnikov product is obtained exclusively, while employing 1,4-bis(diphenylphosphino)butane (dppb) as the ligand favors the formation of the anti-Markovnikov product. A range of functional groups and electron-poor, -neutral, as well as electron-rich styrene derivatives are tolerated by the reaction, providing the desired products in moderate to good yields.

General and Efficient Intermolecular [2+2] Photodimerization of Chalcones and Cinnamic Acid Derivatives in Solution through Visible-Light Catalysis.

[2+2] Photocycloaddition, for example, the dimerization of chalcones and cinnamic acid derivatives, is a unique strategy to construct cyclobutanes, which are building blocks for a variety of biologically active molecules and natural products. However, most attempts at the above [2+2] addition have focused on solid-state, molten-state, or host-guest systems under ultraviolet-light irradiation in order to overcome the competition of facile geometric isomerization of nonrigid olefins. We report a general and simple method to realize the intermolecular [2+2] dimerization reaction of these acyclic olefins to construct cyclobutanes in a highly regio- and diastereoselective manner in solution under visible light, which provides an efficient solution to a long-standing problem.

Carboxylation of Aromatic and Aliphatic Bromides and Triflates with CO by Dual Visible-Light-Nickel Catalysis.

We report the efficient carboxylation of bromides and triflates with K CO as the source of CO in the presence of an organic photocatalyst in combination with a nickel complex under visible light irradiation at room temperature. The reaction is compatible with a variety of functional groups and has been successfully applied to the synthesis and derivatization of biologically active molecules. In particular, the carboxylation of unactivated cyclic alkyl bromides proceeded well with our protocol, thus extending the scope of this transformation.

A sustainable synthesis of 2-aryl-3-carboxylate indolines from N-aryl enamines under visible light irradiation.

With visible light irradiation of a catalytic amount of Ir(ppy) at room temperature, a number of N-aryl enamines were transformed into their corresponding indoline products in good to excellent yields without requiring any extra additives. This is the first example of the synthesis of indolines via the intramolecular cyclization of enamines under visible light irradiation.

Influence of Surface Chemistry on Adhesion and Osteo/Odontogenic Differentiation of Dental Pulp Stem Cells.

The complex interaction between extracellular matrix and cells makes the design of materials for dental regeneration challenging. Chemical composition is an important characteristic of biomaterial surfaces, which plays an essential role in modulating the adhesion and function of cells. The effect of different chemical groups on directing the fate of human dental pulp stem cells (hDPSCs) was thus explored in our study.

Benzene C-H Etherification via Photocatalytic Hydrogen-Evolution Cross-Coupling Reaction.

Aryl ethers can be constructed from the direct coupling between the benzene C-H bond and the alcohol O-H bond with the evolution of hydrogen via the synergistic merger of photocatalysis and cobalt catalysis. Utilizing the dual catalyst system consisting of 3-cyano-1-methylquinolinum photocatalyst and cobaloxime, intermolecular etherification of arenes with various alcohols and intramolecular alkoxylation of 3-phenylpropanols with formation of chromanes are accomplished. These reactions proceed at remarkably mild conditions, and the sole byproduct is equivalent hydrogen gas.

Photocatalysis with Quantum Dots and Visible Light: Selective and Efficient Oxidation of Alcohols to Carbonyl Compounds through a Radical Relay Process in Water.

Selective oxidation of alcohols to aldehydes/ketones has been achieved with the help of 3-mercaptopropionic acid (MPA)-capped CdSe quantum dot (MPA-CdSe QD) and visible light. Visible-light-prompted electron-transfer reaction initiates the oxidation. The thiyl radical generated from the thiolate anion adsorbed on a CdSe QD plays a key role by abstracting the hydrogen atom from the C-H bond of the alcohol (R CH(OH)R ).

Tracking Co(I) Intermediate in Operando in Photocatalytic Hydrogen Evolution by X-ray Transient Absorption Spectroscopy and DFT Calculation.

X-ray transient absorption spectroscopy (XTA) and optical transient spectroscopy (OTA) were used to probe the Co(I) intermediate generated in situ from an aqueous photocatalytic hydrogen evolution system, with [Ru(bpy)]Cl·6HO as the photosensitizer, ascorbic acid/ascorbate as the electron donor, and the Co-polypyridyl complex ([Co(DPA-Bpy)Cl]Cl) as the precatalyst. Upon exposure to light, the XTA measured at Co K-edge visualizes the grow and decay of the Co(I) intermediate, and reveals its Co-N bond contraction of 0.09 ± 0.

Photocatalytic Hydrogen-Evolution Cross-Couplings: Benzene C-H Amination and Hydroxylation.

We present a blueprint for aromatic C-H functionalization via a combination of photocatalysis and cobalt catalysis and describe the utility of this strategy for benzene amination and hydroxylation. Without any sacrificial oxidant, we could use the dual catalyst system to produce aniline directly from benzene and ammonia, and phenol from benzene and water, both with evolution of hydrogen gas under unusually mild conditions in excellent yields and selectivities.

Radical Addition of Hydrazones by α-Bromo Ketones To Prepare 1,3,5-Trisubstituted Pyrazoles via Visible Light Catalysis.

A novel efficient tandem reaction of hydrazones and α-bromo ketones is reported for the preparation of 1,3,5-trisubstituted pyrazoles by visible light catalysis. In this system, the monosubstituted hydrazones show wonderful reaction activity with alkyl radicals, generated from α-bromo ketones. A radical addition followed by intramolecular cyclization affords the important pyrazole skeleton in good to excellent yields.

Visible Light Initiated Hantzsch Synthesis of 2,5-Diaryl-Substituted Pyrroles at Ambient Conditions.

Irradiation of a mixture of enamines and α-bromo ketones, with a catalytic amount of Ir(ppy)3 by visible light (λ = 450 nm), enables the production of various 2,5-diaryl-substituted pyrroles in good to excellent yields. The key intermediates in this reaction have been identified as alkyl radicals, generated from single-electron transfer from the photoexcited Ir(ppy)3* to α-bromo ketones, which subsequently react with a broad range of enamines to undergo the Hantzsch reaction rapidly at ambient conditions.