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Dual Catalytic Switchable Divergent Synthesis: An Asymmetric Visible-light Photocatalytic Approach to Fluorine-containing γ-Keto Acid Frameworks
摘要： Herein, we describe a novel and efficient method for constructing a series of fluorine-containing γ-keto acid derivatives through combining visible-light photoredox catalysis and chiral Lewis acid catalysis. With this dual catalytic strategy, a variety of chiral γ-keto amides containing a gem-difluoroalkyl group and a series of fluorine-containing α,β-unsaturated-γ-keto esters were successfully constructed with high stereoselectivities, respectively. A series of experiments showed that the chemoselectivity of this process was highly dependent on the fluorine reagents besides the Lewis acid catalysts. This approach facilitates rapid access to γ-keto acid derivatives, an important class of precursors for pharmaceuticals, plasticizers, and various other additives.
关键词： γ-keto acid derivatives,chiral Lewis acid catalysis,visible-light photocatalysis,asymmetric difluoroalkylation
更新于2025-09-10 09:29:36
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Ti <sub/>3</sub> C <sub/>2</sub> T <sub/><i>x</i> </sub> -Based Three-Dimensional Hydrogel by a Graphene Oxide-Assisted Self-Convergence Process for Enhanced Photoredox Catalysis
摘要： Assembly of two-dimensional (2D) layered structures into three-dimensional (3D) macroscopic hydrogel has been an enduring attracting research theme. However, the anisotropic intersheet cross-linking to form Ti3C2Tx MXene-based hydrogel remains intrinsically challenging because of the superior hydrophilic nature of 2D Ti3C2Tx. Herein, Ti3C2Tx MXene is ingeniously assembled into the 3D macroscopic hydrogel under mild conditions by a graphene oxide (GO) assisted self-convergence process. During the process, GO is reduced to reduced graphene oxide (RGO) by virtue of the reduction ability of Ti3C2Tx, leading to the partial removal of hydrophilic oxygen-containing groups and an increase of the hydrophobicity and the π-conjugated structures of RGO, which enables the assembly of RGO into 3D RGO framework. Simultaneously, Ti3C2Tx is self-converged to be incorporated into the RGO framework by intimate interfacial interactions, thereby generating Ti3C2Tx-based hydrogel. The hydrogel with interconnected porous structure holds great potential as a promising material platform for photoredox catalysis. With the incorporation of Eosin Y photosensitizer, the functional Ti3C2Tx-based hydrogel exhibits enhanced photoactivity compared to the powder counterpart and features easy operability. This work enriches the rational utilization of GO/MXene colloid chemistry to design Ti3C2Tx MXene-based hydrogels with improved overall efficacy in practical applications.
关键词： hydrogel,graphene oxide,MXene,self-convergence,redox catalysis
更新于2025-09-10 09:29:36
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Photochemical generation of radicals from alkyl electrophiles using a nucleophilic organic catalyst
摘要： Chemists extensively use free radical reactivity for applications in organic synthesis, materials science, and life science. Traditionally, generating radicals requires strategies that exploit the bond dissociation energy or the redox properties of the precursors. Here, we disclose a photochemical catalytic approach that harnesses different physical properties of the substrate to form carbon radicals. We use a nucleophilic dithiocarbamate anion catalyst, adorned with a well-tailored chromophoric unit, to activate alkyl electrophiles via an SN2 pathway. The resulting photon-absorbing intermediate affords radicals upon homolytic cleavage induced by visible light. This catalytic SN2-based strategy, which exploits a fundamental mechanistic process of ionic chemistry, grants access to open-shell intermediates from a variety of substrates that would be incompatible with or inert to classical radical-generating strategies. We also describe how the method’s mild reaction conditions and high functional group tolerance could be advantageous for developing C–C bond-forming reactions, for streamlining the preparation of a marketed drug, for the late-stage elaboration of biorelevant compounds and for enantioselective radical catalysis.
关键词： radicals,SN2 pathway,alkyl electrophiles,photochemical,C–C bond-forming reactions,visible light,enantioselective radical catalysis,nucleophilic organic catalyst
更新于2025-09-10 09:29:36
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Synthesis, Characterisation and Applications of Polymer–Silica Core–Shell Microparticle Capsules
摘要： Encapsulation is a powerful method for the targeted delivery of concentrated reagents, as well as capture of valuable materials in dilute systems. To this end, many encapsulation schemes for specific scenarios have been devised, that incorporate chemospecificity or stimulus response in terms of uptake or release. However, an encapsulation platform that enables highly tailorable surface chemistry for targeting, stimulus response, and core chemistry for capture and release of reagents remains elusive. Here we present such a system comprising composite core–shell capsule particles of hydrophilic polymers coated with thin silica layers, synthesised via straightforward one-pot syntheses. Silica is found to encapsulate a range of polymer hydrogels through a mechanism independent of the specific core chemistry. The hybrid materials possess significantly enhanced rigidity, while allowing surface modification through simple yet versatile silane coupling reactions without a reduction in the functionality of the core. They are shown to have applications as diverse as recyclable catalysis and controlled delivery vehicles for agrochemicals. The successful synthesis and utilisation of this catalogue of materials indicates the broader capability of simple composite structures in an array of high value applications.
关键词： catalysis,silica,microgel,encapsulation,Hybrid materials
更新于2025-09-10 09:29:36
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Direct C–H Arylation Polymerization to form Anionic Water-Soluble Poly(3,4-ethylenedioxythiophenes) with Higher Yields and Molecular Weights
摘要： A facile and environmentally benign Pd-catalyzed direct C–H arylation polymerization (DAP) has been developed for the syntheses of homo- and copolymers of anionic-group-functionalized 3,4-ethylenedioxythiophenes with high yields (up to 99%), high molecular weights, and narrow polydispersities. The effects of various Pd catalysts, phosphine ligands, and additives on the properties of the polymers have been examined. The method gives anionic poly(3,4-ethylenedioxythiophenes) with higher molecular weights than those produced by the previously reported chemical or electrochemical methods. The method was also used to synthesize polymers functionalized with carboxylic acid groups without the need for protection/deprotection steps. The resulting polymers can be processed from water or highly polar organic solvents. We also demonstrated a phosphine-free, water-mediated, Pd-catalyzed DAP. The anionic poly(3,4-ethylenedioxythiophenes) were stable in water, and are promising for applications in sensors, drug delivery, and cell engineering.
关键词： polyethylenedioxythiophenes,C–H arylation,polymerization,anionic polymers,step-economic syntheses,palladium catalysis
更新于2025-09-10 09:29:36
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Enantioselective Allylic Alkylation with 4-Alkyl-1,4-dihydropyridines Enabled by Photoredox/Palladium Cocatalysis
摘要： Highly regio-, and enantioselective allylic alkylation has been achieved enabled by the merger of photoredox and palladium catalysis. In this dual catalytic process, alkyl radicals generated from 4-alkyl-1,4-dihydropyridines act as the coupling partners of the π-allyl palladium complexes. The generality of this method has been illustrated through the reaction of a variety of allyl esters with 4-alkyl-1,4-dihydropyridines. This mechanistically novel strategy expands the scope of the traditional Pd-catalyzed asymmetric allylic alkylation reaction and serves as its alternative and potential complement.
关键词： π-Allyl Palladium Complexes,Palladium Catalysis,4-Alkyl-1,4-dihydropyridines,Photoredox Catalysis,Enantioselective Allylic Alkylation
更新于2025-09-09 09:28:46
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[Topics in Organometallic Chemistry] || Green Cross-Coupling Using Visible Light for C–O and C–N Bond Formation
摘要： The development of green and sustainable approaches in organic synthesis can provide an environmentally friendly method in the industrial manufacture. Recently, visible-light-mediated photocatalysis has achieved great progress and been a powerful tool to the construction of new chemical bonds in the green synthetic community. This chapter provides an updated summary of visible-light-mediated cross-coupling for C–O and C–N bond formations. Compared with the traditional synthetic methods, the visible-light catalysis provides a new way for the useful compounds synthesis (O-containing and N-containing molecules).
关键词： Visible light,C–O bond,Photoredox catalysis,C–H functionalization,Cross-coupling,C–N bond
更新于2025-09-09 09:28:46
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Plasmon-Enhanced Electrocatalytic Properties of Rationally Designed Hybrid Nanostructures at a Catalytic Interface
摘要： In recent years, a promising role of plasmonic metal nanoparticles (NPs) has been demonstrated toward an improvement of the catalytic efficiency of well-designed hybrid electrocatalysts. In particular, the coupling of plasmonic functionality with the metal-based core–shell architectures in plasmon-enhanced electrocatalysis provides a sustainable route to improve the catalytic performances of the catalysts. Herein, the rationally designed AuNPs wrapped with reduced graphene oxide (rGO) spacer along with PdNPs (AuNP@rGO@Pd) as the final composite are reported. The rGO is proposed to promote the reduction of PdO, greatly enhance the conductivity, and catalytic activity of these nanohybrid structures. The plasmon-enhanced electrocatalytic performance of optimized AuNP@rGO(1)@Pd exhibits an ≈1.9- and 1.1-fold enhanced activity for the hydrogen evolution reaction and oxygen evolution reaction, respectively. The final composite also exhibits a superior stability up to 10 000 s compared with the commercial Pd/C. The mechanism of the enhanced catalytic performance is monitored through in situ X-ray absorption spectroscopy by observing the generated electron density under light irradiation. The results demonstrate that the energetic charge carriers are concentrated in the incorporated PdNPs, allowing higher catalytic performances for the overall water-splitting reaction. The conclusions herein drawn are expected to shed light on upcoming plasmon-induced electrocatalytic studies with analogous hybrid nanoarchitectures.
关键词： plasmonic nanoparticles,heterogeneous catalysis,photo-electrocatalysis,oxygen evolution reaction (OER),hydrogen evolution reaction (HER)
更新于2025-09-09 09:28:46
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Lewis-Acid-Catalyzed BODIPY Boron Functionalization Using Trimethylsilyl Nucleophiles
摘要： A novel and straightforward strategy for boron functionalization in boron dipyrromethenes (BODIPYs) is developed. In particular, this synthetic strategy provides new possibilities for the synthesis of sp2 N-substituted (B-NCS and -NCO), benzotriazole- and trifluoroacetamide-substituted BODIPYs that were hitherto unknown. These new BODIPYs display an array of highly desirable photophysical properties (0.04 < Φ f < 0.86), paving the road for further investigations in material applications.
关键词： photophysical properties,boron functionalization,trimethylsilyl nucleophiles,Lewis acid catalysis,BODIPY
更新于2025-09-09 09:28:46
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Stereoselective Intermolecular [2+2] Cycloadditions of Erlenmeyer-Pl?chl Azlactones using Visible Light Photoredox Catalysis
摘要： The first report of the preparation of symmetric and non-symmetric diaminotruxinic derivatives through the photoredox [2+2] cycloadditions of Erlenmeyer azlactones is described, affording the desired compounds in high regio- and diastereocontrol (only head-to-head coupling). Mechanistic studies by DFT suggest that the reaction proceeds through a neutral photocatalytic pathway.
关键词： photoredox catalysis,diaminotruxinic derivatives,[2+2] cycloaddition,Erlenmeyer azlactones,DFT studies
更新于2025-09-09 09:28:46